# Index of underwater diving: A–C

The following index is provided as an overview of and topical guide to underwater diving: Links to articles and redirects to sections of articles which provide information on each topic are listed with a short description of the topic. When there is more than one article with information on a topic, the most relevant is usually listed, and it may be cross-linked to further information from the linked page or section.
Underwater diving can be described as all of the following:
There are seven sub-indexes, listed here. The tables of content should link between them automatically:
* Index of underwater diving: A–C
* Index of underwater diving: D–E
* Index of underwater diving: F–K
* Index of underwater diving: L–N
* Index of underwater diving: O–R
* Index of underwater diving: S
* Index of underwater diving: T–Z

## 0–9

| Contents: Top | 0–9 | A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z |
* 14th CMAS Underwater Photography World Championship – 2013 photography competition held in Cuba
* 1973 Mount Gambier cave diving accident – Scuba cave diving incident in South Australia
* 1982 invasion of the Falkland Islands – Argentine invasion of the Falklands
* 1992 cageless shark-diving expedition – First recorded cageless dive with great white sharks
* 2011 Finswimming World Championships – 2011 swimming competition held in Hungary
* 2013 Finswimming World Championships – International competition in Kazan, Russia
* 2016 Finswimming World Championships – International competition in Volos, Greece
* 2018 Finswimming World Championships – International competition in Belgrade, Serbia
* 35-ton deep-submergence rescue vehicle – Chinese Navy submarine rescue submersible
* 8A4-class ROUV – Chinese work class remotely operated underwater vehicle

## A

| Contents: Top | 0–9 | A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z |
Section contents: Top of section, Aa–Ab, Ac, Ad, Ae, Af–Ag, Ai, Al, Am, An, Ap, Aq, Ar, As, At, Au, Av

### Aa–Ab

* AAI underwater revolver – Six-round amphibious revolver for naval use
* A Blueprint for Survival (cave diving) – Book on cave diving safety by Sheck Exley
* ABISMO – Japanese remotely operated underwater vehicle for deep sea exploration
* ABLJ – Configuration of diving buoyancy compensator

### Ac

Section contents: Top of section, Aa–Ab, Ac, Ad, Ae, Af–Ag, Ai, Al, Am, An, Ap, Aq, Ar, As, At, Au, Av
* Acceptable risk – Risk that is understood and tolerated
* Accelerated decompression – Decompresssion using oxygen-rich breathing gases
* Acoustic beacon – Device that emits a sound signal to aid location underwater
* Acoustic positioning system – System for tracking and navigation of underwater vehicles or divers using acoustic signals
* Active addition rebreather – Semi closed circuit rebreather type
* Active cooling – Cooling methods that expend energy to cool a system or component
* Active heating – Directed application of an external heat source to control thermal balance
* Acute dysbaric disorder – Injury caused by short term exposure to pressure variation
* Acute oxygen toxicity – Adverse effects of high partial pressures of oxygen on the central nervous system

### Ad

Section contents: Top of section, Aa–Ab, Ac, Ad, Ae, Af–Ag, Ai, Al, Am, An, Ap, Aq, Ar, As, At, Au, Av
* Adaptive diving – Scuba diving using techniques modified to compensate for disabilities
* Adaptive Support Diver – Scuba diver trained to support divers with disabilities
* Adjustable buoyancy life jacket (ABLJ) – Chest inflation type buoyancy compensator
* Administrative controls – Class of occupational hazard control
* ADS 2000 atmospheric diving system – US Navy armoured diving suit
* ADS amphibious rifle – Russian bullpup assault rifle for combat divers
* Advanced diver (disambiguation) – Ambiguous term
* Advanced Diving Equipment Company – American manufacturer of surface supplied diving helmets
* Advanced European Scientific Diver – A diver competent to organise a scientific diving team
* Advanced Open Water Diver – Recreational scuba diving certification slightly above minimum entry level
* Advanced open-water diver – Recreational scuba diving certification level slightly above minimum entry level
* Advanced nitrox diver – Technical diving qualification to use multiple mixtures of oxygen enriched air
* Advanced SEAL Delivery System – Former Navy SEAL mini-sub deployed from submarines
* Advanced trimix diver – Recreational technical diving certification to use hypoxic trimix

### Ae

Section contents: Top of section, Aa–Ab, Ac, Ad, Ae, Af–Ag, Ai, Al, Am, An, Ap, Aq, Ar, As, At, Au, Av
* Aeris (dive gear) – American brand of scuba equipment
* Aerosinusitis – Barotrauma of the sinuses
* Aerospace Medical Association – Professional organization in aviation, space, hyperbaric and environmental medicine
* Aer-Sub – Branding used by Cressi-Sub for scuba equipment

### Af–Ag

* AFLOLAUN – Apparatus for laying out line and underwater navigation
* Aggressive decompression – Decompression practice accepting higher risk of DCS to reduce in-water time

### Ai

Section contents: Top of section, Aa–Ab, Ac, Ad, Ae, Af–Ag, Ai, Al, Am, An, Ap, Aq, Ar, As, At, Au, Av
* AIDA Hellas – National representative of AIDA International in Greece
* AIDA International (AIDA) – Worldwide rule- and record-keeping body for competitive breath-hold events
* Air diving – Underwater diving using air as the breathing gas
* Air embolism – Vascular blockage by air bubbles
* Air-integrated dive computer – Dive computer which displays cylinder breathing gas pressure
* Air integration – Use of the dive computer to display cylinder gas pressure
* Airlift (dredging device), also known as air-lift (dredging device) – Dredging device using injected air to move water and entrained load up a pipe
* Airlift dredge – Dredging device using injected air to move water and entrained load up a pipe
* Airlift dredging – Removing underwater sediment using an airlift pump
* Air line – Tube or hose carrying a compressed air supply
* Air-line diving, also known as airline diving – Basic mode of surface-supplied underwater diving
* Airlock, also known as air-lock – Compartment for transfer between environments with different atmospheres
* Air lock diving bell – Type of mobile pressure caisson
* Air lock diving-bell plant – Underwater work support barge used at Gibraltar
* Air spread – The topside base for surface-supplied air diving operations
* Air top, also known as air top-up – Modifying or completing a gas blend by adding compressed air

### Al

Section contents: Top of section, Aa–Ab, Ac, Ad, Ae, Af–Ag, Ai, Al, Am, An, Ap, Aq, Ar, As, At, Au, Av
* Alert Diver – Quarterly magazine published by DAN
* Algal bloom – Spread of planktonic algae in water
* Alpazat cave rescue – Six British soldiers trapped in a flooded Mexican cave
* Al-Sabehat – Iranian swimmer delivery vehicle
* Alternative air source – Emergency supply of breathing gas for an underwater diver
* Alternative air supply – Emergency supply of breathing air for an underwater diver
* Alternative ascent system – Buoyant object with ascent line carried by scuba diver to control ascent
* Alternative gas supply – Emergency breathing gas supply
* Alternobaric vertigo – Dizziness resulting from unequal pressures in the middle ears
* Altitude decompression – Reduction in ambient pressure due to ascent above sea level
* Altitude diver – Diver competent to plan decompression at altitude
* Altitude Diver – Diver qualification for the skills to decompress at altitude
* Altitude diving – Underwater diving at altitudes above 300 m
* Aluminaut – First aluminum hulled submarine

### Am

Section contents: Top of section, Aa–Ab, Ac, Ad, Ae, Af–Ag, Ai, Al, Am, An, Ap, Aq, Ar, As, At, Au, Av
* Ama (diving) – Japanese pearl divers
* Ambient pressure – Pressure of the surrounding medium
* Ambient pressure at depth – Pressure in an underwater environment
* American Academy of Underwater Sciences (AAUS) – American diving standards organisation
* American Canadian Underwater Certifications (ACUC) – Recreational diver training and certification agency
* American Nitrox Divers International (ANDI) – Recreational diver training and certification agency
* Amontons' law – Relationship between pressure and temperature of a gas at constant volume

### An

Section contents: Top of section, Aa–Ab, Ac, Ad, Ae, Af–Ag, Ai, Al, Am, An, Ap, Aq, Ar, As, At, Au, Av
* Anchor pattern – Arrangement of anchors allowing precise positioning of a vessel
* Andersson, Erik – Swedish manufacturer of standard diving equipment
* Ankle strap (diving) – Staps worn over the ankles of dry suits to prevent the boots from pulling off when in use
* Ankle weights (diving) – Diver trim weights worn at the ankles
* ANMP – Association nationale des moniteurs de plongée
* ANSTI breathing simulator, also known as ANSTI machine, ANSTI breathing machine – Machine to measure work of breathing of diving apparatus
* Anti-fog – Chemicals that prevent the condensation of water as small droplets on a surface
* Anti-frogman techniques – Methods of protection from incursions by divers and swimmers
* Antipodes (submersible) – Commercial submarine built in 1973
* AN/WQX-2 – Diver detection sonar used in defense against underwater incursions
* Anxiety – Unpleasant emotion

### Ap

Section contents: Top of section, Aa–Ab, Ac, Ad, Ae, Af–Ag, Ai, Al, Am, An, Ap, Aq, Ar, As, At, Au, Av
* AP Diving – British manufacturer of underwater diving equipment
* Apeks – British manufacturer of scuba diving equipment
* Apnea blackout – Loss of consciousness caused by cerebral hypoxia towards the end of a breath-hold dive
* Apnea finswimming, also known as Apnoea finswimming – Underwater swimming in a swimming pool using mask, monofin and holding one's breath.
* Apparatus for laying out line and underwater navigation (AFLOLAUN) – Equipment used by early cave divers
* Apparent weight – Weight of an object when a force additional to gravity is present
* APS underwater rifle – Soviet underwater assault firearm firing unrifled steel flechettes

### Aq

Section contents: Top of section, Aa–Ab, Ac, Ad, Ae, Af–Ag, Ai, Al, Am, An, Ap, Aq, Ar, As, At, Au, Av
* Aqua Lung America – American company manufacturing recreational diving equipment
* Aqua Lung/La Spirotechnique – French company manufacturing breathing apparatus and diving equipment
* Aqua-Lung – Original name for open-circuit scuba equipment
* Aquanaut – Diver who remains at depth underwater for longer than 24 hours
* Aquarium diving – Occupational diving in large aquariums
* Aquascope – Underwater viewing device
* Aquathlon (underwater wrestling) – Competitive underwater wrestling
* Aqueon – Diver powered propulsion device

### Ar

Section contents: Top of section, Aa–Ab, Ac, Ad, Ae, Af–Ag, Ai, Al, Am, An, Ap, Aq, Ar, As, At, Au, Av
* Archaeological diving – Method in underwater archaeology
* Archaeology of shipwrecks – Study of human activity through the analysis of shipwreck artifacts
* Archimède – French Navy bathyscaphe
* Archimedes' principle – Buoyancy principle in fluid dynamics
* Argox – Gas mixture occasionally used by scuba divers for dry-suit inflation
* Army engineer diver – Armed forces occupation
* Army Ranger Wing – Special operations force of the Irish Defence Forces
* Artificial gills (human) – Hypothetical devices to extract oxygen from water
* Artificial reef – Human-made underwater structure that functions as a reef
* Artificial Reef Society of British Columbia (ARSBC) – Canadian non-profit to create artificial reefs for habitat enhancement and recreation
* AR vest – Type of jacket harness for surface-supplied diving

### As

Section contents: Top of section, Aa–Ab, Ac, Ad, Ae, Af–Ag, Ai, Al, Am, An, Ap, Aq, Ar, As, At, Au, Av
* Ascending and descending (diving) – Procedures for safe ascent and descent in underwater diving
* Ascent and descent (diving) – Procedures for safe ascent and descent in underwater diving
* Ascent blackout – Loss of consciousness caused by cerebral hypoxia on ascending from a deep freedive
* Ascent rate (diving) – Speed at which the diver ascends from a dive
* Ascents and descents (diving) – Procedures for safe ascent and descent in underwater diving
* Ascent to altitude after diving – A type of extended decompression
* ASM-DT amphibious rifle – Russian folding stock underwater firearm
* Asphyxia – Severely deficient supply of oxygen
* Assisted ascent – An emergency ascent during which the diver is provided with breathing gas by another diver
* Association nationale des moniteurs de plongée – French recreational diver training and certification agency
* Association of Offshore Diving Contractors (AODC) – Precursor to International Marine Contractors Association
* Association of Diving Contractors International (ADCI) – Non-profit organization for promoting standards and knowledge for commercial diving

### At

Section contents: Top of section, Aa–Ab, Ac, Ad, Ae, Af–Ag, Ai, Al, Am, An, Ap, Aq, Ar, As, At, Au, Av
* Atlantis ROV Team – High-school underwater robotics team from Whidbey Island, Washington, United States
* Atmospheric diving suit – Articulated pressure resistant anthropomorphic housing for an underwater diver
* Atmospheric diving system – Diving equiment that isolates the diver from ambient pressure
* Atmospheric pressure diving, also known as atmospheric suit diving – Diving in an articulated pressure resistant anthropomorphic housing
* Atmospheric pressure – Static pressure exerted by the weight of the atmosphere
* Atrial septal defect – Human heart defect present at birth
* Attitude (diver) – Alignment of the principle axes of a diver in the water

### Au

Section contents: Top of section, Aa–Ab, Ac, Ad, Ae, Af–Ag, Ai, Al, Am, An, Ap, Aq, Ar, As, At, Au, Av
* Australian Diver Accreditation Scheme (ADAS) – Australian based international occupational diver accreditation organisation
* Australian Submarine Rescue Vehicle Remora – Diving bell operated by the Australian Navy
* Australian Underwater Federation (AUF) – Governing body for underwater sports in Australia
* Auto-dump valve (ADV) – Valve to release excess gas from a dry suit
* Automatic diluent valve (ADV) – Demand valve to maintain volume of a rebreather loop
* Autonomous diver, also known as Autonomous Diver or Autonomous scuba diver – International minimum standard for entry level recreational scuba diver certification
* Autonomous Robotics Ltd – UK company developing an autonomous underwater vehicle
* Autonomous underwater vehicle – Uncrewed underwater vehicle with autonomous guidance system
* AUV-150 – Unmanned underwater vehicle in development in by Central Mechanical Engineering Research Institute
* AUV Abyss – Autonomous underwater vehicle for mapping of the seabed and water column data collection

### Av

* Avascular necrosis (AVN) – Death of bone tissue due to interruption of the blood supply
* Avelo (diving system) – Variable density scuba buoyancy control system
* Avesta Jernverks AB – Swedish manufacturer of seamless steel gas cylinders

## B

| Contents: Top | 0–9 | A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z |
Section contents: Top of section, Ba, Be, Bi, Bl, Bo, Br–Bs, Bu–By

### Ba

* Bachrach, Arthur J. – American psychologist and administrator (1923–2011)
* Back flow (plumbing) – Undesirable reversal of flow
* Back gas – Scuba breathing gas carried on the back of the diver
* Back kick (finning) – Finning technique to move backwards
* Back-mounted scuba – Scuba set carried on the diver's back
* Backplate and wing – Type of back-mount scuba harness
* Backscatter – Reflection which reverses the direction of a wave, particle, or signal
* Backup diving equipment – Equipment carried in case of failure of the primary equipment
* Backward kick (finning) – Finning technique to move backwards
* Bagwork (concrete placement) – Method of concrete placement
* Bail-out cylinder, also known as bailout cylinder – Emergency gas supply cylinder carried by a diver
* Bailout (diving) – To switch over to an emergency system during a dive
* Bailout block – Valve block on diver's equipment for switching between main and emergency gas supply
* Bailout bottle – Emergency gas supply cylinder carried by a diver
* Bailout gas – Emergency breathing gas supply carried by the diver
* Bailout rebreather – Diving rebreather carried as an emergency gas supply
* Bailout set – Emergency gas supply scuba carried by a diver
* Bailout system – System to provide emergency breathing gas to a diver
* Bailout to emergency gas supply – Diver switching to backup breathing gas
* Bailout to open circuit, also known as bail out to open circuit – Abort a rebreather dive and surface using open circuit scuba
* Bailout to rebreather – Use of a closed circuit breathing apparatus as an emergency gas supply
* Bailout valve – Valve opening the supply of emergency breathing gas
* Bailout valve (rebreather) – Valve on rebreather mouthpiece to switch to emergency gas supply
* Baited remote underwater video – Equipment for estimating fish populations
* Band mask – Heavy duty full-face diving mask for surface-supplied diving
* Barodontalgia – Tooth pain caused by ambient pressure change
* Barostriction – Obstruction of pressure equalization passages
* Barotrauma – Injury caused by external fluid pressure
* Barotrauma of ascent – Injuries caused by a reduction in ambient pressure
* Barotrauma of the ear – Pressure injury to the ears
* Barotraumas of decompression – Injuries caused by a reduction in ambient pressure
* Barton, Otis – American diver and actor (1899–1992)
* Basic Cave Diving: A Blueprint for Survival – Book on cave diving safety by Sheck Exley
* Basic dive boat – Dive boat with minimal facilities
* Basic life support – Emergency medical care by first responder
* Bathyscaphe – Free-diving self-propelled deep-sea submersible

### Be

Section contents: Top of section, Ba, Be, Bi, Bl, Bo, Br–Bs, Bu–By
* Beebe, William – American ornithologist, marine biologist, entomologist, and explorer (1877–1962)
* Behnke, Albert R. – US Navy physician and diving medicine researcher
* Belize Barrier Reef – Series of coral reefs straddling the coast of Belize
* Bell-bounce dive – Surface-oriented diving in a closed bell
* Bell bounce diving – Surface oriented diving using a closed bell
* Bell cursor – Device to guide and control a diving bell near and above the surface
* Bell gas panel – Manifold of hoses and cables provifing services to a diving bell and divers
* Bell handling system – Launch and recovery equipment for a diving bell
* Bell harness – Underwater diving safety haeness
* Bell stage – Platform below the chamber of a closed diving bell
* Bell umbilical – Bundle of hoses and cables providing services to a diving bell
* Bellman (diver) – Diver working as standby diver and umbilical attendant from a diving bell
* Bellman (diving) – The member of a dive team who acts as stand-by diver and tender from the diving bell
* Bellows counterlung – Type of rebreather volume compensation component
* Benemec Oy – Manufacturer of dive computers
* Benign water – Diving environment with very low risk
* Benign water diving – Diving in environments of low risk
* Bering Sea Gold – Television series
* Bering Sea Gold: Under The Ice – Discovery Channel reality television series
* Bert, Paul – French zoologist, physiologist and politician (1833–1886)
* Beuchat – French manufacturer of underwater diving equipment

### Bi

Section contents: Top of section, Ba, Be, Bi, Bl, Bo, Br–Bs, Bu–By
* Bifin – Swimfin type with single foot pocket
* Bikkers – Dutch manufacturer of standard diving equipment
* Biological hazard – Biological material that poses serious risks to the health of living organisms
* BioMarine – American manufacturer of diving rebreathers

### Bl

Section contents: Top of section, Ba, Be, Bi, Bl, Bo, Br–Bs, Bu–By
* Blackpool decompression tables – Decompression tables for compressed air work
* Black-water (diving) – Oceanic mid-water at night
* Black-water diving – Open ocean mid-water diving at night
* Blackout of ascent – Loss of consciousness caused by cerebral hypoxia on ascending from a deep freedive
* Blauhöhle – Flooded cave system in Southern Germany
* Blood–air barrier – Membrane separating alveolar air from blood in lung capillaries
* A Blueprint for Survival – Book on cave diving safety by Sheck Exley
* Blood shift – Set index article
* Blood shift (diving) – Blood flow to the extremities redistributed to the head and torso during a breathhold dive
* Blood–air barrier – Membrane separating alveolar air from blood in lung capillaries
* Błotniak – One-man wet cabin underwater craft designed in Poland in 1978
* Blue Grotto (Malta) – Sea caverns in Malta
* Blue hole – Marine cavern or sinkhole, open to the surface, in carbonate bedrock
* Blue Hole (New Mexico) – Sinkhole used for scubadiving in New Mexico, United States
* Blue Hole (Red Sea) – Submarine sinkhole north of Dahab, Egypt
* Blue Lake (Utah) – Large geothermal pond in Utah, U.S.
* Blue-water diving, also known as blue water diving – Diving in mid-water where the bottom is out of sight
* Blue-water (diving) – Oceanic mid-water
* Blue-water downline – A weighted line suspended from a floating support in deep water

### Bo

Section contents: Top of section, Ba, Be, Bi, Bl, Bo, Br–Bs, Bu–By
* Boarding stirrup – A suspended step to help divers lift themselves from the water into a boat
* Boat diving – Procedures specific to diving from boats
* Boaty McBoatface – British autonomous underwater vehicle
* Bolt snap – Sprung slide gated snap hook
* Bond, George F. – US Navy physician and diving medicine and saturation diving researcher
* Booster pump – Machine to increase pressure of a fluid
* Bottom gas – Gas breathed during the deep part of a dive
* Bottom time – Elapsed time underwater until th start of ascent to the surface
* Bottom timer – An electronic instrument that records depth and elapsed time data on an underwater dive
* Bounce dive – Non-saturation dive profile with meaning depending on context
* Boyle, Robert – Anglo-Irish scientist (1627–1691)
* Boyle's law – Relation between gas pressure and volume

### Br–Bs

Section contents: Top of section, Ba, Be, Bi, Bl, Bo, Br–Bs, Bu–By
* Bradner, Hugh – American physicist, neoprene wetsuit inventor (1915–2008)
* Braile, also known as brail (diving) – Metal strap for clamping the collar of a standard diving suit to the corselet
* Brazilian commando frogmen – GRUMEC is the special forces unit of the Brazilian Navy
* Breaking wave, also known as surf – Wave that becomes unstable as a consequence of excessive steepness
* Breastplate (diving), also known as corselet (diving) – Lower part of a heavy diving helmet
* Breath-hold blackout – Loss of consciousness caused by cerebral hypoxia towards the end of a breath-hold dive
* Breathing – Process of moving air in and out of the lungs
* Breathing air – Air quality suitable for safe breathing
* Breathing air compressor – Machine that compresses atmospheric air at breathing gas quality
* Breathing apparatus – Equipment allowing or assisting the user to breath in a hostile environment
* Breathing gas – Gas used for human respiration
* Breathing gas analysis – Detection and measurement of components of a breathing gas
* Breathing gas quality – Purity requirements for gases for human breathing
* Breathing gas reclaim system – Equipment to recover helium based breathing gas after use by divers
* Breathing gas regulator – Mechanism to control the pressure of a breathing gas
* Breathing gas switch – Changing between breathing gasses of different composition while diving
* Breathing loop – Breathing gas circuit in a rebreather
* Breathing performance of regulators, also known as breathing regulator performance – Capacity of breathing regulators to function as specified
* Breathing regulator – Mechanism to control the pressure of a breathing gas
* Breathing set – Equipment allowing or assisting the user to breath in a hostile environment
* Breathing tube (breathing apparatus) – Tube through which to breath ambient pressure air
* Briggs Marine – A marine services company based in the United Kingdom
* British commando frogmen – Special Boat Service, whose members are drawn largely from the Royal Marines
* British Divers Marine Life Rescue – United Kingdom charity organisation
* British Freediving Association (BFA) – British affiliate to AIDA International
* British Octopush Association (BOA) – National body for underwater hockey in the United Kingdom
* British Sub-Aqua Club (BSAC) – Recreational diving club, training and certification agency based in the UK
* British Underwater Sports Association (BUSA) – British affiliate to the world underwater federation sports committee.
* Brubakk, Alf O. – Norwegian decompression researcher (1941–2022)
* BRUV – Video system for estimating fish populations
* BSAC First Class Diver – Recreational diver competent to lead a group of divers carrying out a project
* BSAC London Branch – Original British Sub-Aqua Club branch

### Bu–By

Section contents: Top of section, Ba, Be, Bi, Bl, Bo, Br–Bs, Bu–By
* Bubble decompression model – Decompression models based on limiting growth of bubble nuclei
* Buddy bottle – Alternative name for scuba bailout set
* Buddy breathing – Technique for sharing breathing gas from a single mouthpiece
* Buddy check – Pre-dive safety checks carried out by two-diver dive teams
* Buddy diver – Person diving by the buddy system
* Buddy diving – Practice of mutual monitoring and assistance between two divers
* Buddy line – A tether between two scuba divers to prevent separation in low visibility
* Buddy separation – Situation where dive buddies are not close enough to communicate
* Buddy separation procedure – Standard procedure for dive buddy separation
* Bühlmann, Albert A. – Swiss physician and decompression researcher (1923–1994)
* Bühlmann decompression algorithm, also known as Buhlmann algorithm – Mathematical model of tissue inert gas uptake and release with pressure change
* Bühlmann decompression model – Mathematical model of tissue inert gas uptake and release with pressure change
* Built-in breathing set – System for supply of breathing gas on demand within a confined space
* Built-in breathing system (BIBS) – System for supply of breathing gas on demand within a confined space
* Built-in breathing system regulator – Hyperbaric chamber breathing regulators that exhaust externally
* Buoyancy – Upward force that opposes the weight of an object immersed in fluid
* Buoyancy compensator (BCD), also known as buoyancy control device – Equipment for controlling the buoyancy of a diver
* Buoyancy compensator inflation hose – Inflation gas supply hose on scuba regulator
* Buoyancy control (disambiguation)
* Buoyancy control in scuba diving, also known as buoyancy control (scuba), or buoyancy control (scuba diving) – Essential safety skill
* Buoyancy control equipment – Diving equipment primarily intended to modify buoyancy of the diver
* Buoyancy control skills – Skills of maintaining neutral buoyancy on scuba
* Buoyancy control with a rebreather – Closed circuit scuba diving skill
* Buoyancy engine – Device that alters a body's buoyancy to provide propulsion
* Buoyant ascent – Type of emergency ascent in diving
* Buoyant tethered ascent, also known as Emergency tethered ascent – Positive buoyancy emergency ascent using a reel upline
* Burst disc, also known as rupture disc – Non-closing over-pressure relief device
* Byford Dolphin – Semi-submersible offshore drilling rig
* Byford Dolphin diving bell accident – Explosive decompression of an occupied saturation chamber

## C

| Contents: Top | 0–9 | A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z |
Section contents: Top of section, Ca–Cc, Ce–Cg, Ch, Ci, Cl, Cm, Co, Cr, Cu, Cy

### Ca–Cc

* Caisson (engineering) – Rigid structure to provide workers with a dry working environment below water level
* Caisson gauge – High precision pressure gauge for pressure vessels for human occupancy
* California Advisory Committee on Scientific and Technical Diving – Precursor to the American Academy of Underwater Sciences
* Cam band, also known as camband, cam strap, or camstrap – Strap with locking buckle to hold scuba cylinder on BCD harness
* Canadian Armed Forces Divers – Underwater divers employed by any of the Canadian armed forces
* Canister light – Dive light with battery pack and light head connected by cable
* Canoe and kayak diving – Recreational diving from a canoe or kayak
* Canoe diving – Recreational diving from a canoe
* Capernwray Dive Centre – Flooded quarry in Lancashire, England, used as a recreational dive site
* Carbon dioxide retention – A tendency to retain abnormally high tissue carbon dioxide levels
* Carbon dioxide scrubber – Device which absorbs carbon dioxide from circulated gas
* Carbon dioxide scrubbing reaction – Chemical reactions that remove carbon dioxide from air
* Carbon monoxide poisoning – Toxic effects of carbon monoxide
* Carleton CDBA – Military rebreather by Cobham plc
* Carmellan Research – British manufacturer of diving rebreathers
* Cascade filling – Efficient system of filling from multiple gas storage cylinders
* Cascade filling system – Filling pressurized gas from a series of storage cylinders
* Cascade storage system – High pressure gas storage system set up for cascade filling
* Catalina Cylinders – American manufacturer of aluminum gas cylinders
* Catastrophic dry suit flooding – Major leak of water into a dry suit
* Caustic cocktail – Mixture of water and strong alkali components from a flooded rebreather scrubber
* Cavalero-Champion – French manufacturer of underwater diving equipment
* Cave Divers Association of Australia (CDAA) – Association to represent cave divers and administrate and support cave diving in Australia
* Cave diving – Diving in water-filled caves
* Cave Diving Group (CDG) – UK based cave diver training and certification agency
* Cave diving helmet – Impact protection equipment worn on the head
* Cave diving regions – Geographical distribution of cave diving venues
* Cave diving regions of the world – Regions of the world where known cave diving venues exist
* Cave line – Line used for navigation in flooded caves
* Cave reel – Line holder used to lay and recover guideline in caves
* Cavern diver – Certification for diving under a natural overhead within the zone of natural light
* Cavern diving – Diving in the part of a cave where the exit is visible by natural light
* C-card – Certification as competent to dive to a specified standard

### Ce–Cg

Section contents: Top of section, Ca–Cc, Ce–Cg, Ch, Ci, Cl, Cm, Co, Cr, Cu, Cy
* C.E. Heinke & Co. Ltd. – British manufacturer of diving equipment
* CEJN connector – Type of quick connector for dry suit inflation gas
* Cenote – Natural pit or sinkhole that exposes groundwater underneath
* Center for Maritime Archaeology and Conservation – Academic centre at Texas A&M University
* Central nervous system oxygen toxicity – Adverse effects of exposure to a high partial pressure of oxygen
* Cerberus (sonar) – Diver detection device
* CGA 850 connector system – US standard connector between scuba regulator and cylinder valve

### Ch

Section contents: Top of section, Ca–Cc, Ce–Cg, Ch, Ci, Cl, Cm, Co, Cr, Cu, Cy
* HMS Challenger K07 – Royal Navy saturation diving support vessel
* Chamber operation – Operation of a hyperbaric chamber in support of underwater diving
* Chamber operator – A person who operates a diving chamber
* Charging pressure – Rated pressure for filling a pressurised gas container
* Charles's law – Relationship between volume and temperature of a gas at constant pressure
* Chase boat – A tender generally not carried by the main vessel
* Checklist – Aide-memoire to ensure consistency and completeness in carrying out a task
* Checkout dive – Short dive to test a skill or equipment
* Chemical hazard – Non-biological hazards of hazardous materials
* Chief of safety – Supervisor of the safety team at a freediving competition
* Christmas tree ladder – Ladder with rungs cantilevered from a central rail
* Chronic dysbaric disorder – Injury caused by long term or multiple exposure to pressure variation
* Chronic oxygen toxicity – Effects of long term exposure to high oxygen concentration

### Ci

Section contents: Top of section, Ca–Cc, Ce–Cg, Ch, Ci, Cl, Cm, Co, Cr, Cu, Cy
* Circular search – Procedure for finding underwater targets
* Circulatory system – Organ system for circulating blood in animals
* Cis-Lunar – Manufacturer of electronically controlled closed-circuit rebreathers for scuba diving
* Civil liability in recreational diving – Legal duty of care, negligence and liability in recreational diving

### Cl

Section contents: Top of section, Ca–Cc, Ce–Cg, Ch, Ci, Cl, Cm, Co, Cr, Cu, Cy
* Clarke, John R. – American scientist and underwater breathing apparatus authority
* Classification of underwater activities – Classification of underwater diving activities by occupational field
* Cleaning and disinfection of personal diving equipment – Prevention of infection by shared or contaminated equipment
* Clearance diver – Navy diver specialist with explosives
* Clearance Divers Life Support Equipment (CDLSE) – British military electronically controlled closed circuit rebreather
* Clearance diving – Military diving work involving underwater demolition and work with explosives
* Clearance Diving Branch (RAN) – Diving unit of the Royal Australian Navy
* Clearing a diving mask – Removing water from a flooded mask underwater
* Clip-on weight – Small weights used to make fine adjustments to a diver's ballast
* Close call – Incident that could have caused harm
* Closed bell – Hyperbaric chamber for transporting divers vertically through the water
* Closed bell emergency procedures – Standard procedures for use in common surface-supplied closed bell diving emergencies
* Closed circuit breathing apparatus, also known as closed-circuit breathing apparatus – Apparatus to recycle breathing gas
* Closed-circuit rebreather, also known as Closed circuit rebreather – Breathing apparatus
* Closed circuit rebreather set point – Settings for maximum and minimum allowable oxygen partial pressure
* Closed circuit scuba – Self contained underwater breathing apparatus which recycles exhaled breathing gas
* Closed circuit bailout – Emergency gas supply from an independent closed circuit rebreather
* Closed-circuit oxygen rebreather – Apparatus to recycle breathing gas
* Closed diving bell – Hyperbaric chamber for transporting divers vertically through the water
* Clump weight – A heavy weight suspended on cable used to guide a diving bell

### Cm

Section contents: Top of section, Ca–Cc, Ce–Cg, Ch, Ci, Cl, Cm, Co, Cr, Cu, Cy
* CMAS* scuba diver, also known as CMAS one-star scuba diver – Entry level recreational diving certification from CMAS
* CMAS** scuba diver, also known as CMAS two-star scuba diver or CMAS** Diver – Autonomous recreational scuba diving certification
* CMAS*** scuba diver, also known as CMAS three-star diver – Fully trained and experienced recreational diver
* CMAS**** scuba diver, also known as CMAS four-star diver – A three-star diver with a high level of competence and broad experience
* CMAS Europe – Non-profit branch of the world underwater federation representing European affiliates
* CMAS Scientific Committee – Committee of the World Underwater Federation
* CMAS Two Star Instructor – CMAS instructor certified to train all core levels of diver
* CMAS Three Star Instructor – CMAS diving instructor trainer
* CMAS Instructors of South Africa (CMAS-ISA) – Member federation of CMAS for South Africa

### Co

Section contents: Top of section, Ca–Cc, Ce–Cg, Ch, Ci, Cl, Cm, Co, Cr, Cu, Cy
* Coastal dive site – Sites in the sea near the coastline
* Cochran Undersea Technology – American manufacturer of dive computers
* Code of practice – Set of written rules which specifies how people working in a particular occupation should behave
* Code of Practice for Scientific Diving (UNESCO) – Principles for the safe practice of diving for science
* Code of Practice for Scientific Diving: Principles for the Safe Practice of Scientific Diving in Different Environments – Document published by UNESCO
* Cold shock response – Physiological response to sudden exposure to cold
* Cold-water diving – Underwater diving in water that is cold enough to require special equipment
* Comando Raggruppamento Subacquei e Incursori Teseo Tesei – Italian special forces diving unit
* Combat rubber raiding craft – Rubberised fabric tactical inflatable boat used by the US Navy
* Combat sidestroke – Variation of side-stroke swimming used by United States Navy SEALs
* Combined gas law – Combination of Charles', Boyle's and Gay-Lussac's gas laws
* Comex therapeutic table CX 30, also known as Comex 30 table – A hyperbaric treatment schedule developed by Comex
* Comhairle Fo-Thuinn (CFT) – Governing body for recreational diving and underwater hockey in Ireland
* Commando Hubert – Combat swimmer unit of the French Navy
* Commandos Marine – Special operations forces of the French Navy
* Commandos Military Unit, also known as Jednostka Wojskowa Komandosów (JWK) – Polish special operations unit
* Commercial diver – Trained and registered professional diver
* Commercial diver registration in South Africa – Registration of commercial divers by the South African Department of Employment and Labour
* Commercial diver training – Processes by which people learn to dive safely for industrial applications
* Commercial diving – Professional diving on industrial projects
* Commercial diving school – Place where commercial diving skills are trained and assessed
* Commercial offshore diver – Professional diver working offshore
* Commercial offshore diving – Professional diving in support of the oil and gas industry
* Communications panel – Surface control panel for underwater diving voice communications system
* Compagnie maritime d'expertises – French offshore diving contractor
* Compass grid search – Technique for finding underwater targets
* Compass search – Search patterns controlled by compass directions
* Competence (human resources) – Ability of a person to do a job properly
* Competitive apnea – Competitive breathhold diving
* Competitive freediving – Breathold diving competition disciplines
* Competitive spearfishing – Hunting of fish underwater on breath-hold using a hand-loaded spear
* Composite-Beat Engel – Swiss manufacturer of composite helmets
* Compressed air – Air under a pressure greater than atmospheric
* Compressed Gas Association (CGA) – American trade association for industrial and medical gas industries
* Compression arthralgia – Joint pain caused by fast compression to high ambient pressure
* Compressor diving – Crude mode of surface-suplied air diving
* Compressor operator – Person competent to operate a diving air compressor
* Concentration – Ratio of part of a mixture to the whole
* Concentration gradient – Variation of concentration of a component of a mixture over distance
* Confédération Mondiale des Activités Subaquatiques (CMAS) – International organisation for underwater activities
* Confined water (diving) – A diving environment that is enclosed and bounded sufficiently for safe training
* Confined water diving – Diving in water which is enclosed and limited in extent
* Conrad Limbaugh Award for Scientific Diving Leadership – Annual award of the AAUS for contribution in scientific diving safety and leadership
* Conservatism (diving) – Approach to risk reduction for decompression
* Conservative decompression – Decompression practices of reduced risk
* Constant flow breathing apparatus – Equipment providing a constant flow of breathing gas
* Constant flow regulator – Gas pressure control regulator which provides a calibrated output
* Constant mass flow regulator – Gas pressure regulator with a constant mass flow delivery
* Constant weight apnea – Freediving discipline
* Constant weight bi-fins – Competitive freediving discipline
* Constant weight without fins – Freediving discipline
* Contaminated water – Water containing high levels of hazardous materials
* Contaminated water diving – Occupational diving in contaminated water
* Continental Shelf Station Two – Undersea research habitat in the Red Sea
* Contingency plan – A plan in case something unexpected occurs
* Continuous blending and compression – Gas blending by constant flow mixing and analysis
* Continuous decompression – Decompression without specific stops at given depths
* Continuous flow breathing apparatus – Equipment providing a constant flow of breathing gas
* Continuous guide line, also known as continuous guideline – Cord that can lead a scuba diver to open water
* Contraindications for hyperbaric medicine – Reasons to avoid therapeutic compression
* Controlled buoyant lift – A technique used by scuba divers to raise an incapacitated diver to the surface
* Controlled emergency swimming ascent (CESA) – Emergency procedure for scuba divers when out of air
* Coral reef – Outcrop of rock in the sea formed by the growth and deposit of stony coral skeletons
* Coral Reef Alliance – Non-profit, environmental NGO focused on protecting coral reefs
* Coral reef protection – Modifying human activities to reduce impact on coral reefs.
* Correct scuba weighting – Weighting for scuba diving which works best most of the time
* Corselet (diving helmet) – Part of a diving helmet supported by the shoulders
* Cosmos CE2F series – Italian swimmer delivery vehicles
* Counterlung – Volume compensating device in a rebreather

### Cr

Section contents: Top of section, Ca–Cc, Ce–Cg, Ch, Ci, Cl, Cm, Co, Cr, Cu, Cy
* Cracking pressure – Pressure difference over the diaphragm needed to open a demand valve
* Cramp – Pathological, often painful, involuntary muscle contraction
* Cressi-Sub – Italian manufacturer of recreational diving and swimming equipment.
* Crewed submersible – Small watercraft able to navigate under water
* Crew resource management – Air crew communication and decision-making training
* Critical flicker fusion frequency – Concept in the psychophysics of vision
* Critical pressure for the dive profile – Minimum safe pressure to start a planned dive profile
* Critical pressure of ascent – Minimum safe gas pressure to start ascent from a given depth and time to surface
* Critical pressure of descent – Minimum safe pressure to start a planned dive profile
* Critical pressure of exit – Minimum safe pressure to turn a penetration dive
* Critical pressure of turnaround – Minimum safe pressure to turn a penetration dive
* Critical pressure (scuba) – Breathing gas minimum safe pressure for starting specified activity
* Cross altitude corrections – Adjustments to the US Navy decompression tables to allow for altitude
* Cryogenic rebreather – Rebreather that removes CO2 by freezing it out using heat exchange with liquid oxygen

### Cu

Section contents: Top of section, Ca–Cc, Ce–Cg, Ch, Ci, Cl, Cm, Co, Cr, Cu, Cy
* CUMA – Canadian military diving rebreather
* Current (hydrology) – Flow of water in a stream caused by gravity
* Current shear – Variation of flow rate transverse to flow direction
* Current (stream) – Flow of water in a natural watercourse due to gravity
* CURV – Early remotely operated underwater vehicle

### Cy

Section contents: Top of section, Ca–Cc, Ce–Cg, Ch, Ci, Cl, Cm, Co, Cr, Cu, Cy
* Cylinder band – Straps to clamp two scuba cylinders together
* Cylinder pressure gauge – Instrument for measuring gas pressure in a storage cylinder
* Cylinder valve (disambiguation)
| Contents: Top | 0–9 | A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z |