# Index of underwater diving: T–Z

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

## T

| 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 |
Subsection: Top of section, Ta, Te, Th, Ti, To, Tr, Tu, Tw, Ty
* T1200 Trenching Unit – Remotely operated seabed trenching unit

### Ta

* Table Marine National MN90, also known as MN90 decompression tables – French navy decompression tables
* Tactical diver – Military scuba diver
* Tactical Divers Group – Special operations force of the Argentine Navy
* Taifib – Indonesian amphibious reconnaissance unit
* Talus cave – Type of cave
* Tank weight – Ballast weight attached to a scuba cylinder
* Taravana – Decompression sickness after breath-hold diving
* Task loading – Relationship between operator capacity and the accumulated activities that must be done

### Te

Subsection: Top of section, Ta, Te, Th, Ti, To, Tr, Tu, Tw, Ty
* Teaching method – Principles and methods used by teachers to enable student learning
* Team gas redundancy – System for sharing backup breathing gas within a dive team
* Team redundancy – System for sharing backup equipment and skill diversity
* Technical diver training – Processes to develop skills and knowledge to dive safely for technical diving
* Technical diving – Extended scope recreational diving
* Technical diving instructor – Person certified to train recreational divers in technical disciplines
* Technical Diving International (TDI) – Technical diver training and certification agency
* Technical Extended Range (TXR) – Recreational scuba and freediving training and certification agency
* Technisub – Italian manufacturer of diving equipment
* Tektite habitat – Undersea laboratory and experimental habitat
* Temperate reef – Hard benthic substrate and ecosystems in cool to cold water in middle latitudes
* Temperature – Physical quantity of hot and cold
* Tension-leg platform – Type of offshore platform used in production of oil or gas
* Tesei, Teseo – Italian naval officer and pioneering military diver
* Test of pressure – Diagnostic technique to identify decompression sickness
* Testing and inspection of diving cylinders – Periodical inspection and testing to revalidate fitness for service
* Tethered ascent, also known as tethered buoyant emergency ascent, emergency tethered ascent, buoyant tethered ascent – Positive buoyancy emergency ascent using a reel upline (required skill for CMAS Self-Reliant Diver)
* Texas Finswimming Association – Official governing body for competitive and recreational finswimming in Texas

### Th

Subsection: Top of section, Ta, Te, Th, Ti, To, Tr, Tu, Tw, Ty
* Thalmann algorithm – Mathematical model for diver decompression
* Thalmann, Edward D. – American hyperbaric medicine specialist and decompression researcher
* Tham Luang cave rescue – 2018 international rescue in Thailand
* The Darkness Beckons – History of UK cave diving by Martyn Farr
* The Last Dive – Non-fiction book by Bernie Chowdhury about a double wreck diving fatality
* Therapeutic decompression tables – Planned hyperbaric exposure profiles to treat decompression sickness
* Therapeutic recompression – Recompression to reduce symptoms of decompression illness
* Thermal balance of the underwater diver, also known as thermal balance of divers – Conditions in which the temperature of a diver can remain stable
* Thermal balance of the saturation diver – Maintaining body heat in the saturation diver
* Thermal comfort zone (TCZ) – Range of temperature and humidity comfortable for people
* Thermal neutral zone (TNZ), also known as thermoneutral zone – Minimal metabolic regulation to retain ambient core body temperature
* Thermal status of the underwater diver, also known as Thermal status of divers
* Thermal undersuit – Insulating undergarments for use with a dry suit
* Thermocline – Distinct layer of temperature change in a body of water
* Thermodynamic model of decompression, also known as Thermodynamic decompression model – Early model in which decompression is controlled by volume of gas bubbles forming in tissues
* Theseus (AUV) – Large autonomous underwater vehicle for laying fibre-optic cable
* The Shaft (sinkhole) – Karst feature in South Australia
* Three bolt equipment – Standard diving dress using three bolts to clamp the helmet bonnet to the corselet
* Three Star Diver – Fully trained and experienced recreational diver
* Through-water communications – Wireless diver voice communications equipment
* Thunderbird cylinders – American manufacturer of seamless aluminum gas cylinders

### Ti

Subsection: Top of section, Ta, Te, Th, Ti, To, Tr, Tu, Tw, Ty
* Tidal race – Fast-moving tidal flow passing through a constriction, forming waves, eddies and strong currents
* Tide – Rise and fall of the sea level under astronomical gravitational influences
* Tillman, Albert – American educator and underwater diver
* Timeline of diving technology, also known as Timeline of underwater diving technology – Chronological list of notable events in the history of underwater diving equipment
* Time to surface (TTS) – Estimated ascent and decompression time from a given point on a dive profile
* Tissue (biology) – Group of similar cells performing a specific function
* Tissue gas loading – Amount of gas dissolved in a tissue
* Tissue slab decompression model – A diffusion limited series tissue decompression model
* Tissue slab diffusion model – Diffusion limited series tissue decompression model

### To

Subsection: Top of section, Ta, Te, Th, Ti, To, Tr, Tu, Tw, Ty
* Toggle bag (concrete placement) – Method of concrete placement suitable for underwater use
* Torricellian chamber – Low pressure air space in a flooded cave chamber
* Total Nitrogen Time (TNT) – Equivalent pressure exposure estimate for a repetitive dive
* Touboulic, Pierre-Marie – French engineer, inventor and writer
* Tourism on the Great Barrier Reef – Service industry in Australia involving recreational diving
* Towboard – Underwater survey equipment used to tow a diver

### Tr

Subsection: Top of section, Ta, Te, Th, Ti, To, Tr, Tu, Tw, Ty
* Training dive – Dive which is part of a training programme
* Training dive sites – Underwater environments selected as suitable for diving skills training
* Transfer chamber – Chamber in a saturation habitat where the bell locks on
* Transfer under pressure (TUP) – Moving between pressurised vessels without decompression
* Transfer under pressure diving – Surface oriented diving from a closed bell and a chamber for decompression
* Travel gas – Gas breathed during the descent part of a dive
* Traverse (cave diving) – A dive the exits from a different access to a cave
* Tremie – Equipment for underwater concrete placement
* Trial diving – Introductory scuba diving experience
* Tribonucleation – Mechanism for creation of microbubbles
* Trieste II – US Navy's second bathyscaphe
* Triger, Jacques – French geologist who invented the pressurised caisson (1801–1867)
* Trim weights (diving) – Diving weights distributed primarily to improve trim
* Trimix blender – Person competent to blend trimix breathing gases for scuba diving
* Trimix (breathing gas) – Breathing gas consisting of oxygen, helium and nitrogen
* Trimix diving – Use of trimix gas blend for underwater diving
* Trimix Scuba Association (TSA) – Recreational technical scuba training and certification agency
* Trongle – Device used on submarines to help swimmers to locate a submerged submarine
* Tropical coral reef – Reefs built by warm-water coral species
* Try-dive – Supervised diving experience to try out diving or equipment

### Tu

Subsection: Top of section, Ta, Te, Th, Ti, To, Tr, Tu, Tw, Ty
* Tubesuit – Active heat transfer undergarment
* TUP, also known as transfer under pressure – Moving between pressurised vessels without decompression
* Turbidity – Cloudiness of a fluid
* Turkish Underwater Sports Federation (TSSF), also known as Türkiye Sualtı Sporları Federasyonu – Turkish national governing body for underwater sport and lifesaving
* Turn pressure – Gas pressure at which the divers start the return from a dive

### Tw

Subsection: Top of section, Ta, Te, Th, Ti, To, Tr, Tu, Tw, Ty
* Twin bladder buoyancy compensator – Scuba diving buoyancy compensator with redundant air bag
* Twin-hose regulator – Scuba regulator with two ambient pressure hoses to the mouthpiece

### Ty

Subsection: Top of section, Ta, Te, Th, Ti, To, Tr, Tu, Tw, Ty
* Type 1 gas cylinder – Seamless metal gas cylinder
* Type 1 wet bell – Open diving bell without onboard gas panel
* Type 2 gas cylinder – Hoop wound composite reinforced gas cylinder
* Type 2 wet bell – Diving bell with onboard gas panel
* Type 3 gas cylinder – Seamless metal gas cylinder core fully wound with composite reinforcement
* Type 4 gas cylinder – Plastic cylinder liner fully wound with composite reinforcement
* Type 904 dive tender – Chinese class of naval diving support vessel

## U

| 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, Ul–Um, Un, Up–Ur, Us, Uw

### Ul–Um

* Ultra deep air diving – Scuba diving on air to very dangerous depths
* Ultrasonic bubble detection, also known as Doppler bubble detection – Detection of vascular bubbles by ultrasonic sensors
* Ultrasonic bubble detection in decompression research – Non-invasive method for detecting vascular bubbles
* Umbilical cable – A cable and/or hose bundle which supplies required consumables to a remote user
* Umbilical management – Safe handling of the diver's umbilical
* Umbilical tending – Management of the supply end of the diver's umbilical

### Un

Section contents: Top of section, Ul–Um, Un, Up–Ur, Us, Uw
* Uncontrolled buoyant ascent – Type of diving accident
* Uncontrolled decompression – Unplanned drop in the pressure of a sealed system
* Undersea and Hyperbaric Medical Society (UHMS) – US based organisation for research and education in hyperbaric physiology and medicine.
* Undersea Medical Society – Original name of Undersea and Hyperbaric Medical Society
* The Undersea World of Jacques Cousteau – Documentary television series about underwater marine life
* Undersuit – Clothing worn under a protective suit
* Undertow (water waves) – Return flow below nearshore water waves.
* Underwater – Aquatic or submarine environment
* Underwater acoustic communication – Wireless technique of sending and receiving messages through water
* Underwater acoustic positioning system – System for tracking and navigation of underwater vehicles or divers using acoustic signals
* Underwater acoustics – Study of the propagation of sound in water
* Underwater archaeology – Study of human activity via evidence found underwater
* Underwater archaeology techniques – Methodology used in underwater archaeology
* Underwater art – Works that are designed for or performed in an underwater environment
* Underwater Bike Race – Annual charity event in North Carolina
* Underwater blackout syndrome – Loss of consciousness caused by cerebral hypoxia towards the end of a breath-hold dive
* Underwater breathing apparatus – Equipment which provides breathing gas to an underwater diver
* Underwater camera housing – Water and pressure resistant container for camera
* Underwater citizen science – The organised collection of underwater data for scientific purposes by volunteers
* Underwater computer vision – Subfield of computer vision
* Underwater concrete placement – Positioning freshly mixed concrete at an underwater location where it is to set
* Underwater construction – Industrial construction in an underwater environment
* Underwater Construction Teams – Navy construction battalion underwater construction units
* Underwater cutting and welding – Metalworking techniques used by underwater divers
* Underwater cycling – Stunt in which a bicycle is ridden under water
* Underwater Defence (Turkish Armed Forces) – Special operations unit of the Turkish Navy
* Underwater demolition – The deliberate destruction or neutralization of man-made or natural underwater obstacles
* Underwater Demolition Command – Special warfare unit of the Greek Navy
* Underwater Demolition Team – US Navy special operations group
* Underwater dive – Instance of underwater diving activity
* Underwater diver – Person who descends below the surface to interact with the environment
* Underwater diver training – Processes by which people develop the skills and knowledge to dive safely underwater
* Underwater divers – People who participate in underwater diving
* Underwater diving – Descending below the surface of the water to interact with the environment
* Underwater diving emergency – Situation that endangers the life or health of a diver
* Underwater diving environment – The underwater environment to which a diver may be exposed
* Underwater diving equipment – Equipment used to facilitate underwater diving
* Underwater diving hazards – Agents and situations that pose a threat to the underwater diver
* Underwater diving on Guam – Recreational diving tourism destination
* Underwater diving safety – Safety and risk management in underwater diving
* Underwater diving terminology, also known as Underwater diving terms – Definitions of technical terms, jargon, diver slang and acronyms used in underwater diving
* Underwater domain awareness – Underwater component of maritime domain awareness
* Underwater environment – Aquatic or submarine environment
* Underwater exploration – Investigating or traveling around underwater for the purpose of discovery
* Underwater Explorers Club – British diving club, now defunct
* Underwater firearm – Firearms that can be effectively fired underwater
* Underwater football – Underwater team sport using snorkeling equipment and an American football
* Underwater glider – Type of autonomous underwater vehicle
* Underwater habitat – Human habitable underwater enclosure filled with breathable gas
* Underwater hockey – Underwater sport of pushing a puck into the opposing goal
* Underwater hockey in Australia
* Underwater hockey in Turkey
* Underwater Hockey Wales – Welsh underwater hockey association
* Underwater Hockey World Championships – International event for the sport of Underwater Hockey
* Underwater ice hockey – Freediving variant of ice hockey played upside-down under the ice
* Underwater inspection – Examination of underwater structure and equipment to assess condition
* Underwater mining – Any mining activity done underwater
* Underwater music – Music composed to be performed or heard underwater
* Underwater navigator – Diver competent to navigate in open water by compass or pilotage
* Underwater Offence (Turkish Armed Forces) – Special operations Forces of the Turkish Navy
* Underwater orienteering – Underwater compass navigation and speed competition on scuba.
* Underwater Orienteering World Championships – International sporting competition
* Underwater painting – Technique of painting underwater
* Underwater photography – Genre of photography
* Underwater photography (sport) – Competitive underwater digital photography on scuba
* Underwater Photography World Championships – International event for the sport of underwater photography
* Underwater pilotage – Diver navigation using natural features
* Underwater Port Security System – Defense against hostile swimmer incursions
* Underwater rescue – Rescue of persons trapped underwater
* Underwater rifle – A man-portable, long-barreled firearm which can be fired effectively underwater
* Underwater rugby – Underwater team sport
* Underwater rugby in Australia – Team breathhold underwater sport
* Underwater rugby in Colombia – Regional sporting activity
* Underwater rugby in the United States – Watersport played on breathhold
* Underwater Rugby World Championships – International sporting competition
* Underwater sculpture – Sculpture made for underwater display
* Underwater search and recovery – Locating and recovering underwater objects
* Underwater search pattern – Techniques for finding underwater targets
* Underwater searches – Techniques for finding underwater targets
* Underwater search pattern – Techniques for finding underwater targets
* Underwater Society of America (USOA) – American national representative organization for underwater sport.
* Underwater sports – Competitive underwater recreational activities
* Underwater sports at the 2013 Bolivarian Games – Finswimming, free-diving and spearfishing events at San Lorenzo island
* Underwater survey – Inspection or measurement in or of an underwater environment
* Underwater surveying – Inspection or measurement in or of an underwater environment
* Underwater target shooting – Breathhold underwater sport of target shooting with a speargun in a swimming pool.
* Underwater tender – Diver who attends to the umbilical of another diver while underwater
* Underwater tending point – Place where the diver's umbilical is restrained or controlled
* Underwater tourism – Recreational visits to underwater sites
* Underwater vehicle – Vehicle intended to operate underwater
* Underwater videographer – Diver trained in the use of video recorders underwater
* Underwater videography – Electronic underwater photography concerned with capturing moving images
* Underwater visibility – Distance at which an object can be seen through water
* Underwater vision – The ability to see objects underwater
* Underwater warfare – One of the three operational areas of naval warfare
* Underwater work – Work done underwater during diving operations
* Underwater wrestling (disambiguation)
* Under way – State of a vessel free to move through the water
* UNESCO Code of Practice for Scientific Diving – Principles for the safe practice of diving for science
* United Diving Instructors (UDI) – Recreational diver training and certification agency
* United States Marine Corps Combatant Diver Course – Military diver training for the US Marines
* United States Marine Corps Force Reconnaissance – USMC deep reconnaissance unit
* United States Marine Corps Reconnaissance Battalions – Reconnaissance assets of Marine Air-Ground Task Force
* United States military divers – Underwater divers employed by the US armed forces
* United States Navy Experimental Diving Unit (NEDU) – The primary source of diving and hyperbaric operational guidance for the US Navy
* United States Navy SEALs – U.S. Navy special operations force
* United States Navy SEAL selection and training – Special forces unit policy and procedures
* Universal Referral Program – System to complete recreational scuba training with another instructor
* Unmanned diving – Underwater diving by autonomous or remotely operated vehicles

### Up–Ur

Section contents: Top of section, Ul–Um, Un, Up–Ur, Us, Uw
* Upstream scuba manifold – Manifold connecting cylinders upstream of the valve
* Upstream valve – Valve which is opened against the pressure differential
* Upwelling – Oceanographic phenomenon of wind-driven motion of ocean water
* URF (Swedish Navy) – Swedish submarine rescue vehicle

### Us

Section contents: Top of section, Ul–Um, Un, Up–Ur, Us, Uw
* U.S. Divers – Manufacterer of scuba diving equipment
* User respiratory interface – Facepiece of a breathing apparatus
* US Navy decompression models and tables – Basis for the published decompression tables and algorithms
* U.S. Navy Diving Manual (USNDM), also known as United States Navy Diving Manual, or US Navy Diving Manual – Training and operations handbook
* U.S. Navy Experimental Diving Unit (USNEDU, NEDU) – The primary source of diving and hyperbaric operational guidance for the US Navy
* US Navy Recompression Treatment Table 6, also known as USN table 6 – Widely used treatment for decompression illness

### Uw

* Uwatec – Manufacturer of dive computers

## V

| 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 |
Subsection: Top of section, Va, Ve, Vi, Vo

### Va

* Validation of decompression models – Experimental confirmation of safety of decompression models
* Valsalva device – Pad in a helmet or mask used to block the nose to assist in ear clearing
* Valsalva maneuver – Technique for equalising pressure in the middle ears
* Valve cracking pressure – Pressure difference needed to open a valve
* Valve knob – Hand grip for turning the valve spindle
* Variable-buoyancy pressure vessel – Type of rigid buoyancy control device
* Variable-buoyancy propulsion – Use of a buoyancy engine to provide propulsion
* Variable density buoyancy compensator – Equipment for controlling the buoyancy of a diver or submersible
* Variable density buoyancy control – Technique for controlling the buoyancy of a diver or submersible
* Variable gradient model – Decompression model using gradient factors that vary non-linearly with depth
* Variable volume buoyancy compensator – Equipment for controlling the buoyancy of a diver
* Variable weight apnea – Deep freediving using a weighted sled for descent, pulling along the depth rope for ascent
* Variable weight apnea without fins – Competitive freediving discipline
* Varying Permeability Model – Decompression model and algorithm based on bubble physics
* Vasa (ship) – 17th-century Swedish warship

### Ve

Subsection: Top of section, Va, Ve, Vi, Vo
* Venting the rebreather loop, also known as venting the loop – Intentionally releasing gas from the breathing circuit}
* Venture One diving accident – Saturation diving fatality in the North Sea in 1977
* Vertical Blue – Freediving competition in The Bahamas at Dean's Blue Hole
* Vertigo – Type of dizziness where a person has the sensation of moving or surrounding objects moving

### Vi

Subsection: Top of section, Va, Ve, Vi, Vo
* VideoRay UROVs – Series of inspection class remotely operated underwater vehicles
* Viewport (diving) – Transparent part of a helmet, submersible, or diving chamber
* Viking (dry suits) – Swedish brand of diving dry suits
* Vintage scuba – Early model scuba equipment and the ongoing activity of diving with it
* Vítkovice Cylinders a.s. – Czech manufacturer of seamless pressure cylinders for gas

### Vo

Subsection: Top of section, Va, Ve, Vi, Vo
* Volumetric gas fraction – Dimensionless quantity
* Voyage to the Edge of the World – 1976 French nature documentary
* VVAL 18 – Mathematical model for diver decompression

## W

| 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, Wa, We, Wi, Wo, Wr

### Wa

* Waage Drill II diving accident – Fatal saturation diving accident in the North Sea in 1975
* Wall diving – Underwater diving alongside a near vertical face
* Walter Kidde and Co – US manufacturer of seamless aluminum gas cylinders
* WASP atmospheric diving system – Type of armoured diving suit without leg articulation
* Water clarity – How deeply visible light penetrates through water
* Water polo cap – Headgear used in water polo and a number of underwater sports
* Waterproof digital camera – Digital still camera with inherently waterproof casing
* Water safety – Human safety in the vicinity of bodies of water
* Water separator – Device to remove condensed water from compressed air
* Water surface searches – Procedures to find objects or persons lost at the surface of a body of water
* Watertight zipper – Zipper closure which prevents water leakage when closed
* Waves and shallow water – Effect of shallow water on a surface gravity wave
* Wave shoaling – Effect by which surface waves entering shallower water change in wave height

### We

Section contents: Top of section, Wa, We, Wi, Wo, Wr
* Weight – Force on a mass due to gravity
* Weight belt – Ballast carried to counteract buoyancy
* Weighted boots (diving) – Shoes with heavy metal soles used as part of a diver's weights
* Weighted shoes (diving) – Shoes with heavy metal soles used as part of a diver's weights
* Weight harness – Webbing system to support diver ballast weights
* Weight pocket – Container on diving equipment to hold ballast
* Welfreighter – British midget submarine of the Second World War
* Wells, John Morgan – Physiologist, aquanaut and researcher (1940–2017)
* Welman submarine – Second World War one-man British midget submarine
* Welsh Association of Sub Aqua Clubs – Welsh national governing body for underwater sport and recreational diving
* Wet bell – Platform for transporting divers vertically through the water
* Wet bell emergency procedures – Standard procedures for use in common surface-supplied wet bell diving emergencies
* Wet Nellie – 1976 car-shaped submarine from the James Bond film The Spy Who Loved Me
* Wet pot – Wet or water filled hyperbaric chamber
* Wet sub – Ambient pressure diver propulsion vehicle
* Wetsuit – Garment worn to provide thermal protection while wet
* Wetsuit boots – Foam neoprene footwear for watersports
* Wetsuit buoyancy – Upwards forece generated by the volume of an immersed wetsuit
* Wetsuit buoyancy loss – Temporary reduction of volume due to compression at depth

### Wi

Section contents: Top of section, Wa, We, Wi, Wo, Wr
* Wienke, Bruce – Bubble model decompression researcher
* Wildrake diving accident – Fatal offshore diving accident in Scotland, 1979
* Willful ignorance – Strategy for attempting to avoid liability
* Willful violation – Deliberate or negligent violation of workplace rules and policies
* Wind generated current – Flow in a body of water generated by wind friction on its surface
* Wind wave – Surface waves generated by wind on open water
* Wireless diver communications – Technology for voice transmission through water
* Wireless pressure transmitter – Cylinder pressure sensor for input to dive computer

### Wo

Section contents: Top of section, Wa, We, Wi, Wo, Wr
* Women Divers Hall of Fame – International honor society
* Woodville Karst Plain Project (WKPP) – Project and organization to map the underwater cave systems of the Woodville Karst Plain
* Work of breathing (WOB) – Energy expended to inhale and exhale a breathing gas
* Working diver – The person who is intended to do the underwater work during a professional dive
* Workplace health surveillance – Ongoing surveillance of workers' health
* World Recreational Scuba Training Council (WRSTC) – Scuba diving standards body
* World Without Sun – 1964 film by Jacques Cousteau
* Worthington Cylinder Corporation – US manufacturer of seamless steel gas cylinders
* Worthington Cylinders GesmbH – Austrian manufacturer of seamless steel pressure cylinders

### Wr

* Wreck Alley – Area off California with several wrecks sunk as artificial reefs
* Wreck diving – Recreational diving on wrecks
* Wreck line – Guide line used in wreck diving
* Wreck penetration diving – Diving inside a sunken shipwreck

## Y

| 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 |
* YMCA SCUBA Program – Defunct recreational diver training and certification agency
* Yoke connector – Clamp to connect scuba regulator to cylinder valve
* Yoke (diving helmet) – Component to prevent accidental removal of a diving helmet

## Α–Ω

| 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 |
* Δ-P (hazard) – Underwater hazard due to strong localised pressure differential