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8. GLOSSARY
Altitude dive A dive made at an elevation above 700 m [2300 ft] above sea-level.
Ascent rate The speed at which the diver ascends toward the surface.
ASC RATE Abbreviation for ascent rate.
Ascent time The minimum amount of time needed to reach the surface in a decompression dive.
ASC TIME Abbreviation for ascent time.
Ceiling On a decompression dive the shallowest depth to which a diver may ascend based on computer
nitrogen load.
Ceiling Zone On a decompression dive the zone between the ceiling and the ceiling plus 1.8 m [6 ft]. This depth
range is displayed with the two arrows pointing toward each other (the “hourglass” icon).
Compartment See “Tissue group”.
DCS Abbreviation for decompression sickness.
Decompression Time spent at a decompression stop or range before surfacing, to allow absorbed nitrogen to
escape naturally from tissues.
Decompression sickness Any of a variety of maladies resulting either primarily or secondary from the formation of nitrogen
bubbles in tissues or body fluids, as a result of inadequately controlled decompression. Commonly
called “bends” or “DCS”.
Dive series A group of repetitive dives between which the instrument indicates some nitrogen loading is
present. When nitrogen loading reaches zero the instrument deactivates.
