Glossary of underwater diving terminology

Glossary of Underwater Diving Terminology

The Glossary of Underwater Diving Terminology is a comprehensive list of terms and phrases used in the field of underwater diving. These terms are used by professional divers, recreational divers, and diving equipment manufacturers to describe diving procedures, equipment, and diving conditions.

A

Absorption: In the context of diving, absorption refers to the process by which a substance, such as a gas, is taken into the body tissues of a diver.

Abyss: The abyss refers to the deepest part of the ocean, typically deeper than 2000 meters. It is a region where no light penetrates and pressure is extremely high.

B

Buoyancy: Buoyancy is the force exerted on an object that allows it to float or rise in a fluid. In diving, buoyancy control is crucial for maintaining depth and preventing uncontrolled ascents or descents.

Buddy: A buddy in diving refers to a partner with whom a diver dives, for safety reasons. The buddy system is a standard practice in recreational and professional diving.

C

Cave diving: Cave diving is a type of technical diving in which divers explore underwater caves. It is considered a high-risk activity due to the potential for getting lost or trapped.

Compressed air: Compressed air is the most common breathing gas used in recreational diving. It is stored in a diving cylinder and supplied to the diver through a regulator.

D

Decompression: Decompression is the process of allowing dissolved gases to leave the body safely, to prevent decompression sickness. This is typically achieved by ascending slowly and making decompression stops at certain depths.

Dive computer: A dive computer is a device used by divers to measure the time and depth of a dive, in order to avoid decompression sickness.

E

Enriched Air Nitrox: Enriched Air Nitrox, often simply referred to as Nitrox, is a breathing gas that contains a higher percentage of oxygen and a lower percentage of nitrogen than air. It allows divers to extend their no-decompression limits.

F

Free diving: Free diving, also known as breath-hold diving, is a form of underwater diving that relies on the diver's ability to hold their breath until resurfacing, rather than using breathing apparatus.

G

Gas blending: Gas blending is the process of creating custom breathing gas mixes for diving, such as Nitrox or Trimix.

H

Hyperbaric medicine: Hyperbaric medicine is the medical specialty concerned with the treatment of diving-related illnesses, such as decompression sickness and arterial gas embolism.

I

Immersion diuresis: Immersion diuresis is the increased production of urine caused by immersion in water, particularly cold water. It is a common phenomenon in divers.

J

J-valve: A J-valve is a type of valve used on a scuba cylinder to automatically supply reserve air when the main supply is depleted.

K

Knot: A knot is a unit of speed used in aviation and maritime contexts, including diving. One knot is equivalent to one nautical mile per hour.

L

Line: In diving, a line refers to a rope or cord used for navigation, measuring distance, or securing equipment.

M

Mixed gas diving: Mixed gas diving is a type of technical diving where divers use a breathing gas other than air, such as Nitrox or Trimix.

N

Nitrogen narcosis: Nitrogen narcosis is a reversible alteration in consciousness experienced by divers who dive to depths greater than 30 meters while breathing air.

O

Oxygen toxicity: Oxygen toxicity is a condition resulting from the harmful effects of breathing molecular oxygen at elevated partial pressures. It is a concern for scuba divers, particularly those using enriched air Nitrox.

P

Partial pressure: In diving, partial pressure refers to the portion of the total gas pressure contributed by an individual gas component in a mixture.

Q

Quarry diving: Quarry diving is a type of inland diving where divers dive in quarries that have been filled with water.

R

Rebreather: A rebreather is a type of breathing set that absorbs the carbon dioxide of a diver's exhaled breath to permit the rebreathing (recycling) of the substantially unused oxygen content, and unused inert content when present, of each breath.

S

Scuba diving: Scuba diving is a mode of underwater diving where the diver uses a self-contained underwater breathing apparatus (scuba), which is completely independent of surface supply, to breathe underwater.

T

Technical diving: Technical diving is a form of scuba diving that exceeds the scope of recreational diving. Technical divers may dive deeper, stay longer, and enter overhead environments.

U

Underwater navigation: Underwater navigation is the technique of finding one's way underwater, often used by scuba divers.

V

Visibility: In diving, visibility refers to the distance a diver can see underwater. It is affected by water clarity and light levels.

W

Wreck diving: Wreck diving is the act of diving on shipwrecks. It can be done recreationally, for research purposes, or for salvage.

X

Xerostomia: Xerostomia, or dry mouth, is a common symptom experienced by divers due to breathing dry compressed air.

Y

Yoke: A yoke is a type of connector used to attach a regulator to a diving cylinder.

Z

Zooplankton: Zooplankton are small animals that drift with the current, and are a major source of food for many marine animals. They can sometimes affect visibility during night dives when attracted by lights.