Here is a glossary of scuba diving terms: Scuba divers exploring fish and coral. ...

A-F

AGE 

arterial gas embolism is a condition that can be caused by a diving accident in which a gas expands due to too rapid ascent, and a bubble and blocks the arterial flow of blood.

Altitude Diving 

diving at a location where the water surface is 2000 feet above sea level or higher, and which requires special dive tables or dive computers to calculate allowed depths and times for safety.

Anoxia 

absence of oxygen caused by inhaling a breathing gas that contains no oxygen or being unable to inhale any breathing gas.

Aqua-lung 

underwater breathing equipment consisting of a diving cylinder and diving regulator.

Barotrauma 

injury caused by pressure

Beach master or dive marshal 

A person on the beach who records when divers enter and exit the water. Typically used during scuba classes to keep track of the students, watch the gear, provide assistance when required.

Bounce dive 

In commercial diving, bounce diving is the alternative to saturation diving. In recreational diving, a bounce dive is a descent to maximum depth and then an ascent back to the surface with the least delay, in a dive profile resembling a spike.

Buddy breathing 

Two divers sharing the same demand valve, generally after an out-of-gas emergency

Buddy system 

Pair or sometimes threesome of divers that dive together as a team for safety.

Buoyancy compensator or BCD, or BC 

diving equipment worn by divers to provide life-saving emergency buoyancy and the ability to control ascent and descent rates.

C-card or Certification card 

proof of completed diver training and evidence of experience.

Carbon monoxide poisoning 

usually due to compressor maintenance errors.

Carbon dioxide poisoning 

is due to incomplete elimination of carbon dioxide.

Compressor 

a machine used to increase the volume of usable air in a diving cylinder by raising its pressure.

Controlled buoyant lift 

a diver rescue technique.

Decompression sickness 

a potentially lethal diving disorder caused by bubbles of inert gases, such as nitrogen or helium, coming out of solution and becoming trapped in the tissues, organs and blood vessels of the body causing symptoms ranging from rashes to death. Also commonly referred to as DCS, or DCI Decompression Illness

Decompression stop 

a pause during the ascent phase of the dive to allow safe release of inert gases from the tissues of the body and avoid decompression sickness.

Decompression tables 

Printed tables that provide divers with a way of avoiding Decompression Sickness by giving the maximum times that can be spent at depth, and by indicating the Decompression Stops and Surface Intervals needed for a particular depth and time profile to be carried out safely.

Decompression buoy 

a small buoy on a line that divers inflate underwater to indicate their location to their boat.

Dive club 

a group of people with an interest in SCUBA diving.

Dive flag 

Flag used by a boat to indicate that it has 'divers down'. Comes in two versions: the international marine (international code letter flag 'A', ) and the red and white flag (red with white diagonal, ).

Dive profile 

a two dimensional representation of the two most important characteristics of the dive that a diver must monitor to dive safely: depth and time. The profile is often used when describing a dive's likely decompression obligation.

Dive shop 

supplier of diving equipment or training, or organizer of dive expeditions.

Dive tables 

see Decompression tables.

Divemaster 

A professional level diver who leads a group of less experienced divers underwater.

Drift diving 

diving in a current.

Drowning 

death caused by inability to inhale anything but water.

Dry suit 

a diving suit designed to thermally insulate and provide protection to the skin of the diver.

Dysbarism 

medical conditions resulting from changes in ambient pressure.

Electro-galvanic fuel cell 

an electrical device used to measure the concentration of oxygen gas in diving equipment.

Equivalent air depth 

a way of expressing the narcotic effect of breathing gas mixtures that contain nitrogen, for example nitrox and trimix.

Frogman 

A scuba diver, particularly a military diver on an undercover mission.

Description An air embolism, or more generally gas embolism, is a medical condition caused by gas bubbles in the bloodstream. ... Asphyxia is a condition of severely deficient supply of oxygen to the body. ... General Name, Symbol, Number oxygen, O, 8 Chemical series Nonmetals, chalcogens Group, Period, Block 16, 2, p Appearance colorless (gas) very pale blue (liquid) Atomic mass 15. ... Air is the most common and only natural breathing gas. ... ... 12 litre and 3 litre steel diving cylinders A diving cylinder or SCUBA tank is used to store and transport high pressure breathing gas as a component of an Aqua-Lung. ... A gas pressure regulator has one or more valves in series, which let the gas out of a gas cylinder in a controlled way, lowering its pressure at each stage. ... Barotrauma is physical damage to body tissues caused by a difference in pressure between an air space inside or beside the body and the surrounding gas or liquid. ... The use of water pressure - the Captain Cook Memorial Jet in Lake Burley Griffin, Canberra. ... It has been suggested that this article or section be merged with Underwater diving. ... Saturation diving is a diving technique that allow divers to remain at great depth for long periods of time, by living under pressure in special living chamber complexes affixed to a diving support vessel, oil platform or other floating work station. ... Recreational diving is a type of diving that uses SCUBA equipment for the purpose of leisure and enjoyment. ... When using the buddy system, pairs and groups of three SCUBA divers dive together and co-operate with each other, so that they can help or rescue each other in the event of an emergency. ... A buoyancy compensator (or buoyancy control device, BC or BCD) is a piece of diving equipment worn by divers to provide: life saving emergency buoyancy both underwater and on the surface. ... The fundamental item of diving equipment used by divers is the SCUBA equipment, such as the Aqualung or Rebreather. ... Diver training is essential for safe diving. ... Carbon monoxide poisoning occurs after the inhalation of carbon monoxide gas. ... Hypercapnia is a condition where there is too much carbon dioxide (CO2) in the body. ... A gas compressor is a mechanical device that increases the pressure of a gas by reducing its volume. ... Layers of Atmosphere (NOAA) Air redirects here. ... 12 litre and 3 litre steel diving cylinders A diving cylinder or SCUBA tank is used to store and transport high pressure breathing gas as a component of an Aqua-Lung. ... The use of water pressure - the Captain Cook Memorial Jet in Lake Burley Griffin, Canberra. ... The controlled buoyant lift is an underwater rescue technique used by scuba divers to safely raise an unconscious diver to the surface from depth. ... Beaching a casualty while providing artificial respiration Diver rescue, following an accident, is the process of avoiding or limiting further exposure to diving hazards and bringing a SCUBA diver to safety. ... Decompression sickness (DCS), the diver’s disease, the bends, or caisson disease is the name given to a variety of symptoms suffered by a person exposed to a reduction in the pressure surrounding their body. ... Divers face specific physical and health risks when they go underwater (e. ... An inert gas is any gas that is not reactive under normal circumstances. ... This article needs cleanup. ... A Decompression Stop is a period of time a diver must spend at a constant depth in shallow water at the end of a dive in order safely to eliminate inert gases from the divers body to avoid decompression sickness. ... Decompression sickness (DCS), the diver’s disease, the bends, or caisson disease is the name given to a variety of symptoms suffered by a person exposed to a reduction in the pressure surrounding their body. ... Dive Tables, Decompression Tables or Tables are printed cards or booklets that allow divers to determine for a particular dive profile and breathing gas, the Decompression stops required for that dive in order to avoid decompression sickness. ... A decompression buoy, deco buoy or delayed SMB is an item of diving equipment used by SCUBA divers to mark their position whilst underwater doing decompression stops. ... Image File history File links Flag_IntA.png International signal flag A This image has been released into the public domain by the copyright holder, its copyright has expired, or it is ineligible for copyright. ... Image File history File links Flag_USdive. ... The fundamental item of diving equipment used by divers is the SCUBA equipment, such as the Aqualung or Rebreather. ... BSAC Nitrox Decompression tables Dive Tables, Decompression Tables or Tables are printed cards or booklets that allow divers to determine for a particular dive profile and breathing gas, the Decompression stops required for that dive in order to avoid decompression sickness. ... Dive Tables, Decompression Tables or Tables are printed cards or booklets that allow divers to determine for a particular dive profile and breathing gas, the Decompression stops required for that dive in order to avoid decompression sickness. ... Drift diving is a type of recreational diving where the diver is transported by the currents caused by the tide. ... It has been suggested that this article or section be merged with Wetsuit. ... Dysbarism refers to medical conditions resulting from changes in ambient pressure. ... An electro-galvanic fuel cell is an electrical device used to measure the concentration of oxygen gas in SCUBA diving and medical equipment. ... General Name, Symbol, Number oxygen, O, 8 Chemical series Nonmetals, chalcogens Group, Period, Block 16, 2, p Appearance colorless (gas) very pale blue (liquid) Atomic mass 15. ... The fundamental item of diving equipment used by divers is the SCUBA equipment, such as the Aqualung or Rebreather. ... In technical diving, the equivalent air depth (EAD) is a way of expressing the narcotic effect of breathing gases such as trimix and heliox. ... Nitrox refers to any gas mixture composed (excluding trace gases) of nitrogen and oxygen; this includes normal air which is approximately 78% nitrogen and 21% oxygen, with around 1% other gases. ... Trimix is a breathing gas, consisting of oxygen, helium and nitrogen, and is often used during the deep phase of dives carried out using Technical diving techniques. ... // This page describes a type of scuba diver. ...

G-L

Gas blending 

filling diving cylinders with gas mixes such as nitrox or trimix.

Gas embolism 

a potentially lethal diving disorder caused by air or other gas bubbles entering the blood stream through wounds.

Hard Hat diving 

Surface supplied diving, generally in professional diving, either wearing a modern diving helmet or the old-style standard diving dress and brass helmet.

Heliox 

a gas blend of Helium and Oxygen in which helium replaces the normal Nitrogen in air allowing diving at greater depths than can be done with air.

HPNS 

High Pressure Nervous Syndrome or Helium Tremors - caused by using breathing gases that contain helium at depth.

Hypercapnia 

carbon dioxide poisoning generally caused by rebreathing your own exhaled carbon dioxide. A big problem at depth especially with rebreathers or high rates of exertion.

Hyperventilation 

either a deliberate and dangerous method intended to extend the duration of a free dive or the body's response to hypercapnia.

Hypoxia 

insufficient oxygen in the body - normally caused by inhaling a breathing gas that contains insufficient oxygen to support normal activities or consciousness.

Hypothermia 

a potentially lethal medical condition caused by cooling the body.

Interstitial emphysema 

gas trapped in the chest after lung barotrauma.

J-Valve 

An early yoke style scuba tank valve that had a lever which activated a reserve pressure release and was commonly used before the submersible pressure gauge was available.

K-Valve 

A standard yoke style valve without a reserve lever.

Kayak diving 

an alternative to boat diving or shore diving where the diver uses a special purpose kayak to get to site.

Log Book 

List of the dives a diver has recorded for proof of experience.

Air, oxygen and helium gas blending system Gas blending or gas mixing is the filling of diving cylinders with non-air breathing gases. ... 12 litre and 3 litre steel diving cylinders A diving cylinder or SCUBA tank is used to store and transport high pressure breathing gas as a component of an Aqua-Lung. ... Nitrox refers to any gas mixture composed (excluding trace gases) of nitrogen and oxygen; this includes normal air which is approximately 78% nitrogen and 21% oxygen, with around 1% other gases. ... Trimix is a breathing gas, consisting of oxygen, helium and nitrogen, and is often used during the deep phase of dives carried out using Technical diving techniques. ... Description An air embolism, or more generally gas embolism, is a medical condition caused by gas bubbles in the bloodstream. ... Divers face specific physical and health risks when they go underwater (e. ... Surface supplied diver at the Monterey Bay Aquarium, Monterey, California Surface supplied diving refers to divers using equipment supplied with breathing gas using an umbilical cord from the surface, often from a diving support vessel but possibly, indirectly via a diving bell. ... Professional diving is diving for payment. ... Diving helmets are worn by divers who need to speak and hear underwater. ... Hardhat diver entering water at Stoney Cove, England A standard diving dress consists of a metallic (copper, brass or bronze) diving helmet, an airline or hose from a surface supplied diving air pump, a canvas diving suit and boots. ... Heliox is a gas that is composed of a mixture of helium (He) and oxygen (O2). ... General Name, Symbol, Number helium, He, 2 Chemical series noble gases Group, Period, Block 18, 1, s Appearance colorless Atomic mass 4. ... General Name, Symbol, Number oxygen, O, 8 Chemical series Nonmetals, chalcogens Group, Period, Block 16, 2, p Appearance colorless (gas) very pale blue (liquid) Atomic mass 15. ... General Name, Symbol, Number nitrogen, N, 7 Chemical series nonmetals Group, Period, Block 15, 2, p Appearance colorless Atomic mass 14. ... HPNS, High Pressure Nervous Syndrome or Helium Tremors is a diving disorder caused by using breathing gases that contain helium at depths in excess of 130 metres / 429 feet. ... Air is the most common and only natural breathing gas. ... General Name, Symbol, Number helium, He, 2 Chemical series noble gases Group, Period, Block 18, 1, s Appearance colorless Atomic mass 4. ... Hypercapnia (from the Greek hyper = above and kapnos = smoke) is a condition where there is too much carbon dioxide (CO2) in the body. ... Hypercapnia is a condition where there is too much carbon dioxide (CO2) in the body. ... A rebreather is a type of breathing set that provides a breathing gas containing oxygen and recycles exhaled gas. ... In medicine, hyperventilation (or hyperpnea) is the state of breathing faster or deeper (hyper) than necessary, and thereby reducing the carbon dioxide concentration of the blood below normal. ... Free-diving refers to various aquatic activities that share the practice of breath-hold diving. ... Hypercapnia (from the Greek hyper = above and kapnos = smoke) is a condition where there is too much carbon dioxide (CO2) in the body. ... Hypoxia is a pathological condition in which the body as a whole (generalised hypoxia) or region of the body (tissue hypoxia) is deprived of adequate oxygen supply. ... Air is the most common and only natural breathing gas. ... General Name, Symbol, Number oxygen, O, 8 Chemical series Nonmetals, chalcogens Group, Period, Block 16, 2, p Appearance colorless (gas) very pale blue (liquid) Atomic mass 15. ... To be more accessible to a general audience, this article or section may require cleanup. ... Barotrauma is physical damage to body tissues caused by a difference in pressure between an air space inside or beside the body and the surrounding gas or liquid. ...

M-R

Maximum operating depth 

the depth at which the partial pressure of oxygen (ppO2) of a gas mix exceeds a safe limit.

Navy SEAL 

A US Navy trained military diver.

Night diving 

a dive at night - many underwater animals are nocturnal or behave differently at night.

Nitrogen narcosis 

condition caused by breathing nitrogen at high pressure (at depth).

Nitrox 

a breathing gas consisting of oxygen and nitrogen

Oxygen toxicity 

is caused by using breathing gases that contain oxygen at high pressure (at depth).

Partial pressure of a gas 

the concentration of individual component gases of breathing gases.

Pneumothorax 

collapsed lung.

Professional diving 

diving for payment.

Rebreather 

breathing equipment that captures, cleanses and re-oxygenates exhaled breath so that it can be re-inhaled.

Recompression chamber 

a pressure vessel used to treat divers suffering from certain diving disorders such as decompression sickness.

Recreational diving 

a type of diving that uses SCUBA equipment for the purpose of leisure and enjoyment.

In technical diving, the maximum operating depth (MOD) of a breathing gas is the depth at which the partial pressure of oxygen (ppO2) of the gas mix exceeds a safe limit. ... In a mixture of ideal gases, each gas has a partial pressure which is the pressure which the gas would have if it alone occupied the volume. ... To meet Wikipedias quality standards, this article or section may require cleanup. ... Night diving is a type of recreational diving which takes place in darkness. ... Nitrogen narcosis or inert gas narcosis is a reversible alteration in consciousness producing a state similar to alcohol intoxication in SCUBA divers at depth. ... General Name, Symbol, Number nitrogen, N, 7 Chemical series nonmetals Group, Period, Block 15, 2, p Appearance colorless Atomic mass 14. ... Nitrox refers to any gas mixture composed (excluding trace gases) of nitrogen and oxygen; this includes normal air which is approximately 78% nitrogen and 21% oxygen, with around 1% other gases. ... Air is the most common and only natural breathing gas. ... General Name, Symbol, Number oxygen, O, 8 Chemical series Nonmetals, chalcogens Group, Period, Block 16, 2, p Appearance colorless (gas) very pale blue (liquid) Atomic mass 15. ... General Name, Symbol, Number nitrogen, N, 7 Chemical series nonmetals Group, Period, Block 15, 2, p Appearance colorless Atomic mass 14. ... Oxygen toxicity or oxygen toxicity syndrome is severe hyperoxia caused by breathing oxygen at elevated partial pressures. ... Air is the most common and only natural breathing gas. ... General Name, Symbol, Number oxygen, O, 8 Chemical series Nonmetals, chalcogens Group, Period, Block 16, 2, p Appearance colorless (gas) very pale blue (liquid) Atomic mass 15. ... In a mixture of ideal gases, each gas has a partial pressure which is the pressure which the gas would have if it alone occupied the volume. ... Air is the most common and only natural breathing gas. ... Left-sided pneumothorax (on the right side of the image) on CT scan of the chest with chest tube in place. ... Professional diving is diving for payment. ... A rebreather is a type of breathing set that provides a breathing gas containing oxygen and recycles exhaled gas. ... A recompression chamber is a pressure vessel used to treat divers suffering from certain diving disorders such as decompression sickness. ... A pressure vessel is a container designed to hold gases or liquids at a pressure different from the ambient pressure. ... Divers face specific physical and health risks when they go underwater (e. ... Decompression sickness (DCS), the diver’s disease, the bends, or caisson disease is the name given to a variety of symptoms suffered by a person exposed to a reduction in the pressure surrounding their body. ... Recreational diving is a type of diving that uses SCUBA equipment for the purpose of leisure and enjoyment. ...

S-Z

Salt water aspiration syndrome 

the diver inhales a mist of sea water from a fault demand valve causing a reaction in the lungs.

Saturation diving 

a decompression regime used in commercial diving that allows divers to live work for weeks at a time where their tissues become saturated in high pressure gas.

Secondary drowning 

can occur hours after a near drowning.

Semi-dry suit 

a wet suit with wrist and ankle seals to reduce entry and exit of water.

Shore diving 

Scuba diving that starts from the shore line.

Skin 

a lycra suit worn by a diver in warm water or under a wet suit.

Solo diving 

diving alone - an alternative to the buddy system.

Standard diving dress 

old-fashioned "hard hat" diving gear.

Subcutaneous emphysema 

gas under the skin tissue.

Submersible pressure gauge or SPG 

Gauge attached to the regulator and used to monitor pressure remaining in the scuba cylinder

Surface detection aids 

equipment, such as flags, SMBs, flares, EPIRBs and whistles, carried by divers to maintain contact with dive boats or attract rescue when lost at sea.

Surface interval 

the time between dives. Divers need to track this time interval for planning decompression for the next dive.

Surface marker buoy, SMB 

a small inflated buoy that divers tow when underwater on drift dives to indicate their location to their boat.

Technical diving 

a form of SCUBA diving that exceeds the scope of recreational diving allowing deeper and longer dives.

Time to fly 

Divers must wait approx. 24 hours after the last dive before flying to reduce the risk of decompression sickness.

Trimix 

a breathing gas consisting of oxygen, helium and nitrogen.

Wall diving 

diving along the face of a vertical wall - requires good buoyancy control because there is no seabed to prevent the diver descending too deep.

Wet suit 

A tightly fitting neoprene thermally-insulating diving suit that allows a limited volume of water inside the suit.

Wreck diving 

diving on shipwrecks.