A type of abseiling point used especially in winter and ice climbing. Also called as V-thread.
The surface of a leaf that is facing away from the stem or trunk. It is situated away or outward from the axis.
The nonliving components of the environment that directly affect plant and animal life, such as water, carbon dioxide, oxygen, and light. Abiotic factors include climatic, edaphic, and physiographic factors.
The process of being removed. Snow ablation usually refers to removal by melting.
The area of a glacier where yearly melting meets or exceeds the annual snow fall.
On or within the boat.
A native inhabitant of a country, especially before colonization.
A stone, typically sandstone or limestone that was used to smooth or sharpen antler, bone, wood and other stone.
The process by which a climber can descend a fixed rope. Also known as Rappel.
The lowest temperature that can possibly be reached in our Universe. Scientists have gotten very close to reaching absolute zero but it is impossible to reach it.
The process by which the products of digestion are transferred into the body's internal environment, enabling them to reach the cells.
Absorptive Feeders (biology)
Animals such as tapeworms that ingest food through the body wall.
The mass of water vapor in the atmosphere per unit of volume of space.
Large, relatively flat areas of ocean floor found at 5,000-6,000m below sea level. If sediments are discharged from a river and deposit relatively quickly onto the plain they may form an abyssal fan.
The adaptation of an organism to environmental changes.
The accumulation of sediment (mud, sand, etc.) by deposition, often occurring along a shoreline or in a river delta.
The net gain in ice mass by precipitation of snow, arrival of snow from avalanche, arrival of snow by wind transport or refreezing of melt water. Is dominant to ablation over space and time when the glacier enters colder conditions.
The degree of sourness of a usually water soluble substance. Acidity is measured in pH, with 7 being neutral and 2 being a strong acid.
Lavas containing high percentage of silica. Tend to have high melting points and to be highly viscous.
Refers to the unnatural increase, through human pollution, in the acidity of water precipitation. Most commonly sulphuric and nitric acids formed from by-products of fossil-fuel burning and metal smelting.
Animals that do not have a coelom or body cavity; e.g., sponges and flatworms.
ACR (Alpine Cock Ring)
An anchor method similar to a cordelette but that is dynamically equalizing. It employs a cord and a rappel ring.
Having or experiencing a rapid onset and short but severe course.
Having a luster like that of a diamond.
An alteration in the structure or function of an organism by natural selection, that helps it survive in its environment.
The diversification of a species as it adapts to different ecological niches. If successful, the species become specialized for the new environments (the mechanism being natural selection), and they eventually evolve into different species.
A small fin between the dorsal and tail fin.
A South-facing slope.
Floating free with the currents and tide, not under control.
A thin blade mounted perpendicular to the handle on an ice axe that can be used for chopping footholds.
Soil transported from one area to another by wind.
Aerial Feeders (rainforest)
Plants that live in trees and obtain nutrients from the air.
Any root exposed to the air.
A stream or river that flows into a larger one; a Tributary.
A basic tent shape, the cross section of which resembles an "A".
A style of tent that has a pole supporting the middle of the tent while the tent walls drape over the pole in an A shape. (other A-Frame Shelters)
Small earthquakes that occur after a large earthquake.
A line of zero compass declination, along which the compass needle "points" to both true and magnetic north.
(Also called ashfall) Volcanic ash that falls from an ashcloud or a volcanic column.
A very large body of atmosphere defined by essentially similar horizontal air temperatures. Moisture conditions are also usually similar throughout the mass.
The force put on a given area by the weight of the air around it.
Air Scent (hunting)
Scent carried by the wind.
A bird that lands and doesn't move or falls dead in the air and hits the ground is often said to be "air washed" and gives off very little scent on the ground and is difficult for dogs to find.
An animal or plant that has less pigment than normal. An albino animal usually has skin that appears white or transparent; white or nearly colorless hair, feathers, or scales; and pink or blue eyes with a deep-red pupil. An albino plant has less of the chemicals that give plants their normal colors.
A belay ledge that is surrounded by vertical rock on all sides.
Plant-like organisms that live in water. They are very simple organisms; they have no roots, no stem, and no leaves.
An instrument, or part of an instrument , for determining direction, either horizontal or vertical . In its simplest form, a peepsight or telescope mounted on a straightedge and used for plotting directions graphically. In such instruments as transits and theodolites, the alidade is the part containing the telescope and its attachments.
Measure of the amount of acid neutralizing bases.
A combination of two or more metals.
Clay, silt, gravel, or similar detrital material deposited by running water.
A large, fan-shaped pile of sediment forming at the base of narrow canyons onto a flat plain at the foot of a mountain range.
Soils deposited through the action of moving water. These soils lack horizons and are usually highly fertile.
Unconsolidated gravel, sand, silt and clay deposited by streams.
Alpha male or female
The strongest male or female of a species in a small geographic area.
Roughly the area on a mountain above the treeline. The treeline is the line where trees stop growing on a mountain.
Alpine Glacier (also called mountain glacier)
a glacier that forms on mountains.
Alpine Knee (climbing)
To use your knee as a way to gain ground on a climb.
Alpine Start (climbing)
To make an efficient start on a long climb by packing all your gear the previous evening and starting early in the morning, usually well before sunrise.
An instrument that measures elevation by using barometric (air) pressure.
The height above sea level.
A medical condition that is often observed at high altitudes. Also known as Acute mountain sickness, or AMS. (more about altitude sickness)
A huge tropical rainforest located in the vicinity of the Amazon River.
In the middle of the ship.
Animal with smooth, moist skin; it has gills when young and then develops lungs when older. Frogs, toads, and salamanders are amphibians.
The unpaired fin that lies along the midline of the body beneath the anus, usually on the back half of the fish.
An arrangement of one or (usually) more pieces of gear set up to support the weight of a belay or top rope.
Anchor Point (hunting)
One of the most important aspects of developing good form is to develop a "consistent" anchor point. An anchor point is a consistently repeatable indexing point somewhere near your ear, cheek, behind your ear (if you’re a release shooter), or possibly your lip or cheek, if you are a "fingers" shooter. The point can be most anywhere on you face, as long as it is at your full draw length, and preferable at a place that is easily repeatable. Without a consistent anchor point you will never develop good form, and accuracy.
Anchor Rode (boating)
The line or chain attached to your anchor.
A type of volcanic rock. This gray to black rock is composed of about 54 to 62 percent silica, plus some iron and magnesium.
A device that measures wind velocity.
Chest pain, especially during physical exertion or emotional stress, that is caused by gradual blockage of the coronary arteries.
A seed plant that produces flowers.
A pullover jacket. Anoraks are practical because there is no zipper running top to bottom that can fail or let your body warmth escape when moving.
A line of latitude located at 66°30' south, delineating the Southern Frigid Zone of the Earth.
A hard coal containing little volatile matter.
A substance which prevents blood-clotting.
The growths of bone-like material portruding from the skull of a male member of the deer family. Antlers are shed annually. On rare occasions, female cervids also grow antlers. Antlers are sometimes called "horns" in hunting vernacular, although this term is incorrect.
Aphotic Zone (ocean)
Bottom most layer of the ocean zones, where light does not reach.
The path or route to the start of a technical climb. Although this is generally a walk or, at most, a scramble it is occasionally as hazardous as the climb itself.
Aquatic means elating to the water. Aquatic animals are adapted to living in the water most of the time (as opposed to living on the land, in the air, or in trees). Fish, dolphins, and river otters are examples of aquatic animals.
An underground layer of loose rock, sand, or gravel that holds water in its spaces.
A medieval crossbow that needed a windlass to draw the bowstring back.
Able to live in trees, like a parrot or iguana.
A group or chain of islands clustered together in a sea or ocean.
A mass of very cold, dry air that usually originates over the Arctic Ocean north of Canada and Alaska.
A line of latitude located at 66°30' north, delineating the Northern Frigid Zone of the Earth.
A sharp, narrow mountain ridge. It often results from the erosive activity of alpine glaciers flowing in adjacent valleys.
A general term used to describe areas suffering from lack of rain or drought. More specifically, a condition in which evaporation exceeds precipitation.
brightly coloured seed-covering which attracts animals to eat it.
Arkansas Call (hunting)
A single reed duck call used by hunters in flooded timber.
A medium-hard mineral stone used for putting a fine edge on knives.
Arm Guard (hunting)
A protective device worn on the bow arm to protect it in case of a string slap.
Arrow Fletcher (hunting)
Tool used to precisely aligned feathers or vanes that are being glued to an arrow during manufacturing.
Arrow Saw (hunting)
A high-speed abrasive blade is used, along with an adjustable setting to precisely cut an arrows length.
A person who makes metal arrowheads.
Arrow Spinner (hunting)
A device for visually inspection an arrows "trueness" (shaft straightness, point or broadhead, or nock alignment), used by placing an arrow supported on each end, between two free running rollers. The arrow is spun quickly, and you can visually check to see if all components run true, or run "out."
Arrow Straightener (hunting)
A tool consisting of a precision "dial type indicator," roller supports for each end of the arrow, and an arm used to apply pressure to the arrow to bend it "straight" by using the indicator as a guide.
A deep gully cut by a stream that flows only part of the year; a dry gulch. A term normally used only in desert areas.
The channel of an ephemeral or intermittent stream in the semiarid Southwest, usually with a flat-floor and vertical banks of unconsolidated material two feet or more high. Sometimes called a wady.
Thick-walled vessels that carry blood away from the heart.
The group of animals with hard exoskeletons made of chitin, segmented bodies and jointed limbs. Insects, arachnids, uniramians, trilobites, crustaceans, and others are arthropods.
To climb a rope using aid device.
A device which assists in ascending a rope.
A tall narrow cabinet in which bows and arrows are kept.
(Also called airfall) Volcanic ash that falls from an ashcloud or a volcanic column.
The direction a slope faces. A hillside facing east has an eastern aspect.
Assembly Call (hunting)
A long series of yelps made by hens trying to locate a flock of scattered poults. Used in fall hunting.
Behind the boat.
Region between Mars and Jupiter where most asteroids are found.
The study of space and the heavenly bodies.
A book or bound collection of maps, sometimes with supplementary illustrations and graphic analyses.
The blanket of gases that surrounds the Earth. Used in a sentence: burr, it's cold in here, it must be something in the atmosphere. (see more about the atmosphere)
A ring (or partial ring) of coral that forms an island in an ocean or sea.
Atomic Belay (climbing)
A fast method for setting up a two-point anchor in sport climbing, using the climbing rope to attach to the anchor points.
Made up of protons and neutrons in a central nucleus surrounded by electrons. The smallest particle of a chemical element that can take part in a chemical reaction without being permanently changed.
A carpenter's tool boat builders use for boring holes in wood.
Avalanche (see more about avalanches)
A large mass of falling and / or sliding material. Avalanches can be composed of rock, snow, soil, or ice.
An imaginary line the Earth rotates around.
Same as bearing. Refers to the degree of bearing from your current position to a landmark or destination. Reversing the bearing would be known as a back azimuth or back bearing.