ALT alt

ALT, alt. 1. Abbreviation for alternate. 2. Abbreviation for altitude.

alternate In botanical terms, any plant parts (leaves, buds, branches, etc.) arranged singly at the stem nodes (not on opposite sides). They alternate which side of the branch they emerge from.

alternate leaf arrangement

alternate bid An optional bid to the base bid that deducts or adds services or materials and usually increases or decreases the base bid accordingly.

alternate host Either of two plants that a fungus or insect finds necessary to sustain its life. Some insects or diseases must alternate from one plant type to another in their life cycle. These diseases and insects can be eliminated if a large enough area does not have one of the necessary host plants. For example, the wooly apple aphid, which depends on both elms and apple trees; some rust diseases that are dependent on barberry and wheat; or rust diseases dependent on juniper and white pine.

alternating current Electrical current regularly alternating its direction of flow (at a fixed rate) in opposite directions. Power companies use this current to facilitate transmission over long distances.

alternative dispute resolution The resolution of a dispute without litigation.

ALTN Abbreviation for alteration.

alum. Abbreviation for aluminum.

aluminum 1. A silver-white, malleable, metallic element with good thermal and electrical conductivity, resistance to oxidation, and high reflectivity when polished. 2. A metal pres-ent in most soils, but more prevalent in acid soils. It becomes more soluble, more available, and more likely to cause toxicity to plants as soil acidity increases. In strongly acidic soils (5.5 pH or below), this is often a detriment to plant growth and can be toxic to them.

aluminum brass Brass with some aluminum added to increase its corrosion resistance.

aluminum bronze A copper-aluminum alloy having good corrosion resistance.

aluminum plate Flat aluminum sheet material.

aluminum-silicon bronze A copper alloy with aluminum and silicon added to increase strength and hardness.

aluminum sulfate An inorganic fertilizer that is acidic and lowers pH. Aluminum can be toxic to plants if overused.

ALY Abbreviation for alloy.

ambient pressure See working pressure.

ambient sound The noise level in a space that contains only the noise out of one's control such as rushing water, or street traffic, or motors, etc. It is any combination of sounds from external sources close by or far away.

amendment See soil amendment.

amenity Aesthetic characteristics or other features of land development that increase its desirability or its marketability. Amenities may include such things as a unified building design, recreational facilities, security systems, views, landscaping, attractive site design, adjacent open space or water bodies.

ammonium nitrate ament In botanical terms, an indeterminate spike-like (spicate) arrangement of flowers on a stem (inflorescence) having scaly bracts and unisexual flowers with no petals (apetalous).

amentiferous Descriptive of a plant bearing aments.

American Arbitration Association A nonprofit association founded in 1926 to study benefits and techniques of arbitration; offers neutral arbitrators.

American Association of Nurserymen A

trade organization that has now changed its name to the American Nursery and Landscape Association.

American Institute of Architects (AIA)

A professional organization of architects.

American National Standards Institute

(ANSI) Previously known as the American Standards Association. This is an organization of nearly 400 trade associations, technical societies, professional groups, and consumer organizations that establishes standards for materials and devices.

American Nursery and Landscape Association A trade organization providing education, research, and public relations for its members who grow and sell plants or install landscapes. Their web site is (previously known as AAN, American Association of Nurserymen).

American Society for Testing and Materials (ASTM) An organization that performs tests and establishes standard specifications for materials; their standards are usually referred to as ASTM.

American Society of Consulting Arborists

An organization with members dedicated to the protection of the environment by promoting tree and plant life for safety, functionality, and beauty.

American Society of Landscape Architects (ASLA) A national (U.S.) professional organization of landscape architects promoting the analysis, design, management, and stewardship of the natural and built environments through education, advocacy, communication, and fellowship. Their web site is

Americans with Disabilities Act (ADA)

A federal law requiring public facilities to be accessible for those with physical disabilities. (See also Uniform Federal Accessibility Standards.)

ammeter An instrument that measures electric current in amperes.

ammoniacal copper arsenate (ACA) A

waterborne salt preservative for wood. Wood must be pressure treated for this preservative to be effective. It is highly recommended by experts as it is odorless, clean, does not leach, and its color can be masked easily when dry by painting or applying a solid color stain. Besides being good for preserving wood in weather aboveground, this stain can be used for wood placed in water and underground.

ammonia nitrogen A reduced type of nitrogen made as a by-product of organic matter decomposing and synthesizing.

ammoniated superphosphate A compound chemical fertilizer containing 2 to 4% nitrogen, and 14 to 49% available phosphoric acid (phosphorus).

ammonification Bacterial decomposition from organic nitrogen to ammonia.

ammonium nitrate A nitrogen fertilizer with 15% nitrogen (15-0-0). Also known as nitrate of ammonia. It has 32.5 to 34% immediately avail ammonium sulfate able nitrogen. It must have ventilation or it can catch fire or explode. It cakes easily in storage.

ammonium sulfate A nitrogen fertilizer with 21% nitrogen (21-0-0). See sulfate of ammonia.

amp. Abbreviation for ampere.

ampacity A word combining ampere and capacity that expresses the current-carrying capacity of electrical conductors in amperes.

amperage Electric current expressed in amperes.

ampere, amp The standard unit for measuring electrical current that is based on the number of electrons flowing past a given point per second. One volt acting across a resistance of one ohm provides a current flow of one ampere. Many devices and components of wiring systems are rated for the amount of amperes they can safely carry.

amphibious Plants able to live in water or on land.

amphitheater, amphitheatre An outdoor theater, usually semicircular or elliptical, with a stage or area for performances surrounded by seats that rise above the area allowing participants a view of the action, speaker, or displays.

amplexicaul A botanical term referring to some kinds of leaves clasping a stem at their base.

ampliate A botanical term meaning enlarged or dilated.

an- Greek prefix in botanical terms meaning not, from, or without.

anaerobic 1. Any environment low in oxygen or free of it. 2. Living or existing without air. 3. In landscape work, this usually refers to soils that are waterlogged or need aeration to support most plants. Root rot is a common problem in anaerobic soils. See also backfill.

analysis Separation, examination, investigation, and determination of constituent parts, including detailed aspects of a situation, condition, or phenomenon.

anastomosing vein The veins in a leaf forming a complex network. See also dichotomous vein, simple vein.

anchor Something that holds a member or element securely in place.

anchor bolt Usually an L-shaped bolt set in concrete or masonry with its threaded end exposed and pointing upward for fastening materials, structures, or equipment.

anchoring cement Grout placed in sleeves to anchor pipes or tubing in place within them.

anchor roots The roots of plants that give stability to the plant so that it can stand upright and withstand wind.

androecium A botanical term referring to all of the stamens of a flower, considered collectively.

anemometer A device for measuring wind speed. These instruments and the information they produce assist in determining water needs of plant material. They usually consist of cuplike devices held on arms arranged radially around a point where they spin in the wind, allowing recording of speed through a wire.

anemophilous A botanical term describing pollination by wind. (Compare with ento-mophilous, ornithophilous.)

angiosperm The name of the division in the plant classification system indicating inclusion of all flowering plants with seeds that develop in an ovary. They are the most prolific vascular plants on earth. This division is made up of two classes: monocotyledons and dicotyledons. See also taxon.

angle dozer A bulldozer with its blade angled to push the earth to one side.

angle iron An L-shaped iron or steel piece.

angle of repose The maximum slope at which a material can be piled or inclined without sliding or falling. This term is often used in reference to clay materials, piled soil, gravel, or wet concrete.

angle valve A valve for adjusting, turning on, or turning off a flow. This type of valve is configured with its water outlet oriented 90° from its water inlet. It delivers water on a 90° angle from the direction of water entering it.

angular aggregate Aggregate with more sharp edges than rounded edges. It is often produced by crushing.

anhydrate A mineral calcium sulfate useful in Portland cement manufacturing to allow for controlling its set time.

anion A negatively charged ion that is attracted toward the anode during electrolysis. The most common anions in soils and waters are bicarbonate, sulfate, carbonate, nitrate, and chloride ions.

ANLA Abbreviation for the American Nursery and Landscape Association.

annexation The legally binding or recognized inclusion of land into an existing community, city, township, etc., that results in a change in its boundary. Annexation generally refers to the new inclusion of properties just outside a city, town, municipality, etc., but it may also involve the transfer of land from one municipality to another.

annual 1. A plant with a life cycle of one year or less. These plants flower, set seed, and die within one growing season. A winter annual germinates in the fall and fruits the following spring or summer. 2. Yearly or over a 12-month period.

anther annual rings A woody (dicotyledenous) plant's annual circular growth marks of the xylem visible when branches or trunks are cut horizontally (to their longitudinal axis). This is a portion of wood formed in one year of a woody plant's growth. The rings are concentric and become wider and lighter colored with good moisture and sun, and darker and thinner otherwise.

annular nail A nail with tapered rings along its shank, difficult to be removed from a material in which it is pounded. Also called a ring nail.

annulus In plant identification, this means a little ring, and refers to the specialized, thick-walled cells encircling the sporangium of most ferns.

anod. Abbreviation for anodized.

anodize A hard, noncorrosive, electrolytic, oxide film on the surface of a metal.

anodized A metal that has been submitted to electrolytic forces in forming a coat of protective or decorative film.

anoxic The absence of oxygen (both free oxygen and chemically bound oxygen).

ANSI Abbreviation for American National Standards Institute.

anther The part of the stamen of a flower that produces pollen and consists of two pollen sacs with a connecting layer.


anthesis anthesis The period during which a flower is fully expanded and functional.

anthocyanin A glycoside pigment producing blue or red colors in flowers, leaves, or plant parts.

anthracnose A plant disease caused by fungi that exhibit lesions of gray, tan, or dark brown on leaves, stem, fruit, or other parts of the plant. It is most common on ash, maple, elm, oak, sycamore, berry bushes, and many vegetable garden plants. On casual observance, this disease can be mistaken for leaf scorch. However, leaf scorch, also known as hot weather scorch, browns the edges of leaves first, and does not usually cause spotting or interior leaf damage. Wet or damp conditions promote this disease. It is treated by fungicide and/or pruning the affected portions of plants and destroying them (preferably by burning).

anthropomorphic 1. In ecology, connoting human influence. 2. In design, ascribing human characteristics to nonhuman things.

antidesiccant or antititranspirant A material sprayed onto plants to prevent excessive water loss from trunks, foliage, branches, stems, etc. It is sometimes sprayed onto plants before transplanting to reduce moisture loss through transpiration. It can also be helpful during winter when evergreens have their roots frozen (prevents gathering water) or when root-pruning plants.

antislip paint A paint facilitating high friction for foot traffic, assisting in preventing slipping when dry. It has sand, dust, wood, or other material mixed in it.

antimicrobial A substance that kills microbial growth.

anti-siphon valve A device preventing removal or backflow of water or fluids.

ants Insects usually one-half inch long or less with six legs and three distinct body portions. Their bite can be painful; they disturb seeded areas; they spread bacteria and spores; and they disfigure lawns or pavements with residue. Control is by spray, bait, or dust.

APA Abbreviation for American Plywood Association.

apetalous In botanical terms, a flower without petals.

apex 1. In botanical terms, this means tip; uppermost portion; narrowed; pointed; culminating point. 2. The highest point, peak, or tip of any structure.

aphid An insect the size of a pinhead to about one-eighth inch. They are oval, soft, and can be red, green, gray, pink, or black. As they suck on plants, they secrete honeydew, sticky substance that attracts ants and can encourage sooty mold.

aphyllous A botanical term meaning without leaves, or not having normal leaves with blades.

apical In botanical terms, at the apex or summit of an organ.

apical dominance The suppression of side shoot growth by the terminal bud.

apiculate In botanical terms, tipped with a short and abrupt point.

apocarpous A term describing the carpels of a flower being free from each other. (Compare with syncarpous.)

apophysis A botanical term referring to the expanded end portion of a cone scale of Pinus that is exposed when the cone is closed.

APPD Abbreviation for approved.

apple scab This is the most common disease of crabapples and apples. It is caused by the arbor fungus Venturia inaequalis, which grows in cool, moist weather. Spores are carried by the wind in spring. It damages leaves, twigs, and fruit, and can cause fruit and leaves to drop early. To avoid this disease, plant resistant varieties, prune trees to improve airflow for drying after rain, and remove or discard fallen leaves on fruit.

application for payment An application or form prepared by a contractor for payment of work completed.

application rate In irrigation, the rate at which water is applied to a landscape, or the amount of water applied to a given area in one hour. See also precipitation rate.

appraisal A reasonable analysis determining the reasonable value. This is often a requirement on property when sold and is greatly affected by landscape architectural works in place.

appressed In botanical terms, lying close and flat against some other plant part.

approach grafting See inarching.

approved equal Materials, equipment, or methods approved for use in construction as an acceptable equivalent in essential attributes to that which was specified.

approving authority The agency, association, commission, department, or other organization created by law and authorized by the state, county, city, province, township, homeowners, etc. to administer and enforce design and construction requirements.

approx. Abbreviation for approximate.

APZ Abbreviation for agricultural protection zone.

aquaculture The hatching, raising, breeding, and harvesting of fish, or aquatic plants or animals in a natural or artificial aquatic environ ment that requires a body of water such as a pond, river, lake, estuary, ocean, or man-made water body.

aquatic Referring to watery environments. In hydrologic gradient, the aquatic environment begins at emergent wetlands. These environments are characterized by the growth of floating or submerged plants.

aquatic plant A plant that can grow in water whether floating or in saturated soil conditions.

aqueous Relating to water.

aquifer An underground bed or layer that is a water-bearing formation of permeable material capable of yielding groundwater to provide water to springs, wells, etc.

aquifer recharge area An area in which a significant amount of surface water runs into groundwater by: 1. The infiltration into the soil or other rock materials that are directly below the surface: 2. The downward movement of water through the materials that comprise the zone of aeration: 3. The delivery of water into the zone of saturation where it becomes groundwater.

arable A term used to describe land that is capable of growing crops. It is tillable, with nutrients and sufficient other qualities to be suitable for agricultural efforts.

arbitration An effort for dispute resolution in which the involved parties agree to allow a neutral person to hear evidence from both sides and make a final and binding decision. This is nearly always a less costly and faster way to resolve a dipute than through the court systems.

arbor A cover over a walk, gate, patio, or passageway for pedestrians, or a shelter over a significant feature in a landscape made up of vines, branches, or climbing shrubs on latticework, trellises, or wire frames.



arborescent In botanical terms, treelike in size or form, or becoming a tree.

arboretum An ornamental or functional garden for displaying trees, shrubs, and/or herbaceous plants for functional or educational purposes.

arboriculture The cultivation of trees and shrubs, usually for ornamental purposes.

arborist A person skilled and trained in the care and maintenance of trees.

sidewalk\ sprinkler heads \


arc of radius of spray arc 1. In sprinkler irrigation, how far around in a circular pattern (usually expressed in degrees where 360° is a full circle) a sprinkler will rotate or spray. For example, a sprinkler with a 90° arc would spray a quarter-circle pattern. 2. Something arched or curved. 3. A continuous portion of a curved line.

arcade A covered walk with shops, arches, etc. on each side.

arch An overhead curved portion of a structure spanning an opening between two points of the structure.


arch culvert An upwardly curved opening under a road, path, canal, or embankment usually constructed to allow passage of water, traffic, or pedestrians.

arching A term used in plant descriptions depicting a form that arches up and out. In grasses, this term refers to a grass that arches nearly as far to the side of its point of origin (at the ground) as it rises from its point of origin. (Compare with mounded (2), upright grasses, tufted, upright divergent grasses, upright arching grasses.)

artesian well

arching grass

architect 1. A person trained in the design of buildings. 2. A designation reserved by requiring licensure to perform architectural services.

architecture 1. The art and science of designing structures. 2. Structures.

architrave The lowest portion of classical architecture's entablature extending from column to column as a beam. See illustration under entablature.

arch ring In an arched structure, this is the curved portion carrying the load.

arcuate In plant identification and descriptions, a plant part curved into an arc of a circle.

ARC W Abbreviation for arc weld.

arc weld Melting metals together with an electric spark and molten metal from a metallic electrode.

area drain A receptacle or depression designed to collect runoff.

areole Specialized spot-like areas on a cactus stem. They have a rough, uneven, different color (from the rest of the surrounding area), a hard surface, and are usually covered with wooly hair. The spines and flowers of a cactus originate from these spots on the stem.

argenteous In plant identification and botanical descriptions, silvery in color.

argillaceous A botanical term describing something with the nature of clay.

arid climate A climate where precipitation averages less than 10 inches per year.

aril An outside appendage or covering that is formed by some seeds after fertilization as a growth from the ovule stalk.

arillate Pertaining to an aril.

aristate In botanical terms, having awns, or being tipped with an awn or bristle, or being sharply pointed as in the tip of a leaf. (Compare with retuse, cuspidate, emarginate, acuminate, acute, mucronate, obtuse.)

aristate leaf tip

armored cabling Electrical wires with a reinforced protective coating to protect the wires from destructive elements and keep safe those around the cable.

armyworms Larvae of caterpillars usually found in armies denuding plant material in their path. They are eaten by birds, toads, other insects, and skunks. Control with poison is available with bait across their path, sprays, or dusts.

arterial road A road having collector roads allowing traffic access and having more traffic than the collector roads.

artesian well 1. A well made by boring into the ground to a point where an underground supply of water is reached with more pressure than needed to bring it to the surface. This creates a well that flows without the need of a pump. 2. A deeply bored well.

article article In construction specifications, the subdivision of a section that is usually then subdivided into paragraphs, subparagraphs, and clauses.

articulate, articulated In botanical terms, jointed.

artificial marble See artificial stone.

artificial soil mix Any mix for plants to grow in without soil as an ingredient.

artificial stone A mixture of rock portions bonded together.

artisan An individual skilled in an applied art; a craftsman.

AS Abbreviation for automatic sprinkler.

ASA Abbreviation for American Standards Association. See American National Standards Institute.

Asb. Abbreviation for asbestos.

ASBC Abbreviation for American Standard Building Code.

as-built A drawing(s) that shows the construction project as designed with any changes made during construction to give an accurate depiction of actual construction.

ASC Abbreviation for asphalt surface course.

ASCA Abbreviation for American Society of Consulting Arborists.

ASCE Abbreviation for American Society of Civil Engineers.

ascending A term often used to describe branches or other plant parts that angle upward from a plant's vertical trunk, stem, etc. (Compare with spreading.)

asepalous A botanical term describing a flower without sepals.

asexual In botanical terms, propagation without sex.

ascending branching

ash dump An opening in a fireplace through which ashes are swept into an ashpit.

ashes See wood ashes.

ashlar Stone produced for construction purposes having edges with more or less right angles, making it easier to stack. It comes in a variety of sizes.

ashlar brick or rock-faced brick A brick whose face has been beaten to resemble hewn stone.

ashpit A chamber below a fireplace for collecting and removing ashes.

ASI Abbreviation for Architects and Surveyors Institute.

ASLA Abbreviation for American Society of Landscape Architects.

aspect The direction in which a structure or slope faces with respect to the points of a compass.

aspect ratio In a rectangular configuration, an expression of the ratio of the long side to the short side of the rectangle.

asphalt 1. A dark, cement-like material, solid or semisolid, made of bitumens that occur in nature or are refined in coal tar or petroleum atmospheric pressure production. 2. A mixture of bituminous material with an aggregate for pavements.

asphaltic base course A layer of asphaltic concrete under various pavements, used for stability and spreading the load.

asphaltic cement, asphalt cement An asphalt for direct use in the manufacture of bituminous pavements.

asphaltic concrete or asphalt paving or blacktop A mixture of asphalt and aggregate used as paving material over a compacted base. It is usually placed and compacted while hot. For placement without heat, see cold mix.

asphalt joint filler An asphalt product for filling cracks and joints in pavements.

asphalt paper A paper material that has been coated, or impregnated, with asphalt to increase its resistance to wear and water.

asphalt pavement A pavement comprised of a surface mineral aggregate, coated and cemented together with asphalt cement on supporting asphalt layers.

asphalt pavement sealer A product applied to asphalt pavement to prevent deterioration.

asphalt prepared roofing A felt covered with asphalt and mineral material, available in rolls.

asphalt primer A material applied to waterproof surfaces to prepare them for asphalt application.

asphalt prime coat An asphalt primer.

asphalt seal coat A bituminous slurry or aggregate applied to the surface of pavement to waterproof, preserve, and prepare the surface.

asphalt shingle or composition shingle or strip slate Shingles composed of roofing felts coated with asphalt and mineral granules on the exposed surface.

asphalt-shingle nail See roofing nail.

asphalt soil stabilization The treatment of soil with liquid asphalt to improve load-bearing qualities and resistance to erosion.

asphalt surface course A top layer of asphalt pavement.

asphalt tack coat A thin coating of liquid asphalt on a pavement used to produce a bond between the old surface and the asphalt layer to be placed.

asphalt tile A floor tile comprised of asbestos fibers, mineral pigments, asphaltic binders, and finely ground limestone fillers that make a wear-resistant, inexpensive tile.

ASR Abbreviation for automatic sprinkler riser.

assembling bolt A bolt that temporarily holds parts of a structure so that it can be riveted.

associate In a design firm, this is a staff member with a special employment agreement.

Associated Landscape Contractors of America A trade association promoting business management and profitability for its members, consisting of mostly landscape maintenance firms, landscape installation firms, design/build landscape contractors, and interior landscape firms. Their web site is

assurgent A botanical term describing something ascending (stems or branches, etc.).

astler Old term for ashlar.

ASTM Abbreviation for American Society for Testing and Materials.

astroturf Man-made, grass-like, outdoor carpeting.

AT Abbreviation for asphalt tile.

ATF Abbreviation for asphalt-tile floor.

atmospheric pressure The pressure of the weight of air at any particular elevation, usually atmosphere expressed in pounds per square foot. At sea level, the atmospheric pressure is 14.7 psi (33.9 feet of head), and the pressure decreases with increase in elevation. This is important when assuring water will move from a source to the pump for irrigation or water features as there must be more atmospheric pressure than suction loss See net positive suction head available.

atmosphere 1. A unit of pressure equal to the pressure of the atmosphere at sea level, which is approximately 14.7 lb/sq in or 101.325 pascals (760 mm Hg). At field capacity, water can be extracted by plant roots from soil mesopores with suction pressure (osmotic pressure) of about 0.1 to 0.3 atmospheres (1.4 to 4.41 psi). At wilting point, the pressure required to extract water from soil is approximately 15 atmospheres (220.5 psi). This is the point at which most plants can no longer extract water from the soil, causing wilting. 2. A feeling or ambiance created by surroundings such as a formal landscape, waterfall, serene enclosed landscape, etc. 3. The air surrounding the planet; the outer limit of the biosphere having influence on plants with its dust, pollution, humidity, wind movements, and/or temperature variations, etc.

atmospheric pressure or barometric pressure Pressure exerted by the weight of the earth's atmosphere; at sea level, 14.7 lb/sq in (1.01 x 106 pascals), decreasing with elevation above sea level.

atmospheric vacuum breaker This device prevents back siphonage by allowing an atmospheric break in the pipeline. This is accomplished by a check seat, and an air inlet port within a 90° upright elbow area of a pipe. It is a backflow preventer consisting of a float, which moves up or down to allow atmospheric air into the piping system. It is always placed downstream from all shut-off valves. Its air inlet valve closes when the water flows in the intended direction. But, as water stops flowing, the air inlet valve opens, interrupting the possible back siphoning. This type of backflow device must always be installed at least 6 inches above all downstream piping and outlets that allow water to flow or it is not effective. Also, this assembly must not have shut-off valves or obstructions downstream as it cannot be under continuous pressure to be effective because it relies on the release of water pressure both up and downstream to allow the float check to fall admitting air to the pipes, thus preventing the back siphon of water. A shut-off valve would keep the assembly under pressure and allow the air inlet valve (or float check) to seal against the air inlet port, causing the assembly to act as an elbow instead of a backflow preventer. It must not be used for more than 12 hours in any 24-hour period. It may be used to protect against a pollutant, or a contaminant, but may only be used to prevent a back siphoning condition.

atriolum A small atrium.

atrium 1. An open patio or plaza with a building surrounding it. It usually contains plants in pots or open planters. 2. A glass enclosure attached to the side of a building. It usually harbors plants of interest, or is used for culinary purposes.

attached dwelling unit Two or more dwelling units within the same detached dwelling unit structure. There is only one dwelling unit within a detached structure.

attenuate In botanical terms, becoming narrow and thinner in width gradually, or a tapered portion of a plant part becoming gradually quite slender to a tip. It is more extreme and narrowly pointed than acuminate, or acute. (Compare with cuneate, obtuse, cordate, auriculate, sagi-tate, hastate, truncate, oblique.)

auxin attenuate leaf base

attenuate leaf base attenuation Reduction of sound energy or intensity.

Atterberg limits See liquid limit, plastic limit, shrinkage limit.

Atterberg limits test A test of the water content that defines different states of consistency of plastic soils. This test is used to ascertain a soil's change with the addition of water to determine its tendency to become plastic or liquid.

auger 1. The action of drilling or boring. 2. A device used for boring or drilling wood, soil, etc. that may be handheld, hydraulically operated, or operated by gears with an engine or motor.

auger bit A bit used in a drilling or boring device.

auricles In botanical terms, small projecting lobes or appendages often at the base of a plant organ.

auriculate In botanical terms, earlike appendages or having one or more auricles. (Compare with leaf base descriptions of cuneate, obtuse, cordate, attenuate, sagitate, hastate, truncate, oblique.)


AUTO Abbreviation for automatic.

automatic controller A timing device that turns on and off automatic valves or valve in head sprinklers at desired times and intervals without needing someone to be present to turn these sprinkler elements on or off.

automatic drain A drain in a sprinkler system that automatically closes when the sprinkler pipe is pressurized and automatically opens to drain the pipe when water pressure is released. They are spring loaded or use a ball that is forced by water into place where it blocks water flow out of the pipe. Some are only rated for lateral lines with intermittent working pressure, while others are rated for use on main lines where they can withstand constant static pressure without failing. They are used at low points on sprinkler pipes in temperate climates to prevent freeze damage to pipe systems.

automatic sprinkler system In landscape irrigation, a sprinkler system that is turned off and on by an automatic controller at times and intervals within its program capability. Automatic systems are usually controlled by electricity, but the first automatic systems were controlled by small tubes of water using changes in water pressure from the controller to the valves.

automatic timer A timing device that turns on and off automatic valves or valve in head sprinklers at desired times and intervals without requiring someone to be present to turn these sprinkler elements on or off.

automatic valve In sprinkler systems, a valve that opens or closes when actuated by an automatic controller.

autotrophic Creation of organic carbon from inorganic chemicals such as in photosynthesis.

auxin A plant hormone used to stimulate root growth through cell elongation.

available water automatic valve available water (AW) In a soil, the amount of water stored between field capacity and the permanent wilting point. The approximate amount of water capable of being stored in various soil types expressed in inches per inch is as follows: clay, 0.17; silty clay, 0.17; clay loam, 0.18; loam, 0.17; sandy loam, 0.12; loamy sand, .08; sand, 0.06.

avalanche protector A barrier protecting the tracks of excavation equipment from rocks or debris.

AVB Abbreviation for atmospheric vacuum breaker.

avenue 1. Usually a wide, tree-lined street. It is a term of French derivation, meaning an approach or access to a building, usually in the country with regularly planted trees along its length. But it currently describes a wide street with or without trees. 2. An access way.

average daily traffic (ADT) The average number of cars per day that pass over a given point.

AVG, Avg. Abbreviation for average.

AW Abbreviation for available water.

A/W Abbreviation for all-weather.

AWG Abbreviation for American Wire Gauge.

awl A pointed tool used for punching or gouging holes in leather, wood, hardboard, etc.

awl-shaped In botanical terms, sharp-pointed from a broader base.

awn A bristle-like appendage on a plant. In grasses or grains, one of the slender bristles that sometimes terminate the spikelet.

awns awning A roof-like covering over a door, sidewalk, landscape element, or window, made of fabric, metal, glass, or canvas, etc. They are useful for protection from sun, wind, rain, and snow, but are also valued for aesthetics as decorative embellishments and used as signs. They usually project from a wall or roof.

AWPA Abbreviation for American Wood-Preservers' Association.

AWS 1. Abbreviation for all wood screws. 2. Abbreviation for American Welding Society.

AWWA Abbreviation for American Water Works Association.

ax hammer An ax for cutting or shaping rough stone.

axil In botanical terms, the upper angle (its point) between a leaf and the stem, or the point on a plant (being an angle) where a leaf, flower, or branch arises from a stem.


automatic valve azonal soil axillary In botanical terms, something occurring in or at an axil.

axis 1. In botanical terms, the central line of any body or the organ around which others are attached. 2. A straight line indicating the symmetrical center usually down the center of the longest dimension.

azimuth In surveying, the horizontal angle measured clockwise from north to the direction of the object being located.

azonal soil Earthen material in a soil profile characterized by not having discernable horizons and resembling the parent material.

This page intentionally left blank

Homeowners Guide To Landscaping

Homeowners Guide To Landscaping

How would you like to save a ton of money and increase the value of your home by as much as thirty percent! If your homes landscape is designed properly it will be a source of enjoyment for your entire family, it will enhance your community and add to the resale value of your property. Landscape design involves much more than placing trees, shrubs and other plants on the property. It is an art which deals with conscious arrangement or organization of outdoor space for human satisfaction and enjoyment.

Get My Free Ebook

Post a comment