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Glossary - A

AA Assisted Ascent


Alternate Air Source, second demand valve or regulator, sometimes referred to an octopus.
Abaft Behind, toward a vessel's stern.
ABC Airway, Breathing, Circulation
Abeam Off to the side, amidships, at right angles to vessel
Absolute Pressure Absolute pressure is a measure of the pressure exerted on an object from all sources; includes water pressure and atmospheric pressure.            
ABLJ Adjustable Buoyancy Life Jacket. An older style of buoyancy device still used by some divers.
A Clamp A type of fitting for connecting the regulator 1st stage to the cylinder pillar valve.
ACI Assistant Club Instructor. A BSAC instructor qualification.
ACR Air Consumption Rate, same as SAC, Surface Air Consumption.
AD Advanced Diver. A BSAC diver qualification.
Adrift Unattached to shore or bottom, floating out of control
A Flag The international flag 'A' . Used to denote diving activities
AGE Abbreviation for Arterial Gas Embolism. See CAGE.
Aground Touching or stuck on the bottom.
AI Advanced Instructor. A BSAC instructor qualification
Air embolism Bubble of air in the blood stream that causes a blockage.
Alee Away from the direction of the wind. Opposite of windward
algorithm A mathematical formula
Almanac A calender giving time of such events as sunrise and sunset, changes of moon and tides, change in position of celestial bodies, or other special information. Particularly necessary for celestial navigation.
Aloft Above the deck of a boat.
Alternate Air Source Any device a diver can use in place of the primary regulator.
Atmospheric Pressure The amount of pressure the air around us exerts on our bodies at sea level, about 14.7 pounds of pressure per square inc
Alveoli Small air cells in the lungs.
Ambient pressure The surrounding pressure; on land this comes from the weight of the atmosphere; at depth it is the sum of both the weight of the atmosphere and the weight of the water.
Amidships In or near the middle of the boat.
Anchorage A place that is suitable for anchoring considering the wind, current, seas and bottom.
Anoxia The total lack of Oxygen to the tissues. Also see Hypoxia
Anticyclone High Pressure area, usually associated with settled weather, in the Northern hemisphere an anti-cyclone circulates clockwise.
AOW Advanced Open Water. A PADI diver qualification
AP Absolute Pressure
Apnea Cessation of breathing for short intervals of time. If left untreated it will proceed to respiratory arrest.
Argon An inert gas which is very narcotic in the normal diving range, twice that of Nitrogen. It is a good insulator however and sometimes used in diving suits.
Ascent Check Depth A point reached during the ascent where dive time is checked against the plan. This is usually at the first decompression stop or 6m for no-stop dives.
Ascent Rate The speed in which a diver ascends. BSAC recommend 15m/min up to 6m and then 6m/min for the final 6m.
Astern At any point behind the boat, backward.
ATA Atmospheres Absolute
Atmospheric Pressure The local atmospheric pressure produced at a particular altitude by current weather conditions.
Auto Air/Air II A form of alternate air source build into BuddyT stab jackets.
AV Artificial Ventilation
Azimuth Vertical arc of sky from zenith (point of heavens directly above observer) to horizon (line at which earth and sky or sea and sky appear to meet); angular distance of this from a meridian.










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Page last updated on October 16, 2007
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