AAS Alternate Air Source; backup air delivery system carried while diving.
AAUS American academy of Underwater Sciences; academic organization.
ABT Actual Bottom Time; term used in conjunction with dive table calculations.
AC Alternating Current; electrical term.
ACE Awareness & Control through Education; diving proficiency award associated with the Diamond Reef ® buoyancy training system.
A/D Converter Analog to Digital Converter; used in dive computers.
ADP Advanced Diver Program; sponsored by L.A. Dept. of Parks and Recreation Underwater Instructors Association.
ADT Actual Dive Time; term used in conjunction with dive table calculations; refers to the actual time spent at depth during a repetitive dive.
ADV Advanced Design Vest; specific style of buoyancy compensator.
AGE Arterial Gas Embolism; medical term describing a significant pressure-related injury.
AI Assistant Instructor certification.
AIR Alternate Inflation Regulator; piece of diving equipment that incorporates the function of a low-pressure inflator and a spare second-stage regulator.
AKR Anthony's Key Resort; dive operation in Honduras' Bay Island.
ANDI American Nitrox Divers Incorporated; training agency.
ANSI American National Standards Institute; organization that recommends standards to associated industries, including diving.
AOC American Oceans Campaign; environmental organization.
AOW Advanced Open Water certification.
A.S. Associate of Science degree; educational course of study.
ASA American Standards Association; group that has made recommendations for photographic film manufactures.
ASD American Sports Data, Inc. ; private research organization that tracks diving activity in the United States.
ASL American Sign Language.
ATA Atmosphere Absolute; measurement denoting total pressure, often used in association with gas calculations. (1 ATA is equivalent to 1 ATA)
ATM Atmosphere; measurement of pressure equivalent to 14.7 pounds per square inch (psi), 29.92 inches of mercury (Hg), 1.033 kg/cm2, or 1.013 bar.
AWARE, Project Aquatic World Awareness, Responsibility & Education; nonprofit environmental offshoot of PADI.
AWS American Welding Society; professional organization.
BC Buoyancy Compensator (same as BCD); essential piece of scuba equipment.
BCD Buoyancy Control Device; essential piece of diving equipment that helps secure the scuba tank to the diver as well as provides the ability to make buoyancy changes at depth.
B.S. Bachelor of Science degree; educational course of study.
BSAC British Sub Aqua Club; diving certification organization in the United Kingdom.
BTS Beneath the Sea; annual dive consumer exhibition.
BTSI Buoyancy Training Systems Inc. ; company that created the Diamond Reef ® buoyancy training system.
BTU British Thermal Units or calories; measurement of heat.
BWI British West Indies.
C Celsius; temperature measurement. 0 C is equal to 32* Fahrenheit; also Carbon; atomic element
CCDI Charge-Coupled Device Imaging; a chip installed in many video cameras which converts light waves into electrical energy.
CD Course Director; instructor certification.
CDC Center for Disease Control; informational agency.
CDI Certified Dive Instructor; another term for scuba instructor.
CEDAM Conservation, Education, Diving, Archaeology & Museums; nonprofit environmental and educational organization.
CESA Controlled Emergency Swimming Ascent; diving skill.
CF Cubic Foot.
CF/MIN Cubic feet Per Minute; measurement of volume and time.
CGA Compressed Gas Association; professional organization.
CIS CompuServe Information Service; Interactive computer service.
CIWOA Cayman Island Watersports Operators Association.
cm Centimeter; measurement of length.
CMAS Confederation Mondiale des Activities Subaquatiques, also known as the World Underwater Federation; worldwide diving organization.
CMC Center for Marine Conservation; environmental organization.
CNS Central Nervous System; medical term that is usually used when discussing oxygen toxicity.
CO Carbon Monoxide; gas that can present serious problems if found in a diver's air supply.
CO2 Carbon Dioxide; gas exhaled during respiratory process.
CPR Cardiopulmonary Resuscitation; first aid procedure that sustains a person's ventilation and pulse.
CSRA Colorado Scuba Retailers Association; organization of Colorado dive centers.
CTC Canadian Transportation Commission; government agency whose stamp is found on scuba tanks.
CTO Caribbean Tourism Organization; international government association.
CU Close-up shot; used in underwater video production.
CUE Council on Underwater Education; loose organization of certification agencies that suggests training standards.
DAN Divers Alert Network; membership informational organization that serves the recreational diving community.
DC Direct Current; electrical term.
DC Dive Computer; diving instrument that relates pertinent information to its user.
DCI Decompression Illness; refers to a pressure-related injury, either DCS or AGE.
DCIEM Defense and Civilian Institute of Environmental Medicine (Canada); government research organization.
DCIEM tables Dive tables produced by the Canadian Defense and Civilian Institute of Environmental Medicine.
DCR Depth Consumption Rate; air consumption measurement.
DCS Decompression Sickness or the "bends"; pressure-related injury.
DDT Powerful insecticide that can be fatal to marine life.
DEMA Dive Equipment & Marketing Association; association of diving businesses.
DGPS Differential Global positioning System; ultra-precise version of Global Positioning System of long-range satellite navigation. (see GPS)
DIN Deutsches Institut fur Normung; an association that develops and suggests manufacturing guidelines. A DIN valve is a special valve design that screws into the tank valve.
DIVECON Dive Controller; SSI leadership certification.
DLT Direct Line Thrust; design which channels water along a fin blade.
DMAC British Admiralty's Diving Advisory Committee; agency that recommends military diving procedures in the United Kingdom.
DoD Department of Defense; government agency in charge of U.S. military affairs.
DOT Department of Transportation; U.S. government organization whose stamp is found on scuba tanks.
DPV Diver Propulsion Vehicle, also known as "scooter"; mechanical device that propels a diver through the water.
DSC Diving Services Consultants; a private instructor training business.
DSI Divers Security Insurance; a private diving insurance business.
DSRV Deep Submergence Rescue Vehicle; mini-sub designed for rescue.
DT Dive Training magazine.
DTIA Dive Travel Industries Association; group of dive travel-related businesses.
DUI Diving Unlimited International; dry suit manufacturer.
EAN Enriched Air Nitrox; breathing gas with oxygen component greater than 21% oxygen.
EBT Effective Bottom Time; term used with DCIEM dive tables.
E-E Exponential in-Exponential out; term used to relate gas absorption and elimination.
EIS Environmental Impact Statement; study that must be conducted prior to the initiation of any major activity in the U.S.
E-L Exponential in-Linear out; term used to describe gas absorption and elimination.
EMID Emergency Medical Identification; laminated identification card with a microfilm medical history of its owner.
EMS Emergency Medical Services; medical assistance service in North America.
EMT Emergency Medical Technician; medical certification.
EPA Environmental Protection Agency; division of U.S. government responsible of environmental affairs.
EVA Extra Vehicular Activity Training Station; water-filled diving tank used to train astronauts in simulated zero-gravity conditions.
F Fahrenheit; temperature measurement.
FADO Florida Association of Diving Operators.
FDI Florida Diving Institute; private business that trains scuba instructors.
ffw Feet Fresh Water; term that denotes measurements made in fresh water as opposed to seawater.
fpm Feet Per Minute; measurement of distance covered over time used during ascents and descents.
FSM Federated States of Micronesia; island nation located in the Pacific Ocean.
fsw Feet Sea Water; term that denotes measurement in seawater as opposed to fresh water.
ft3 Cubic foot; measurement of volume.
GN Guide Numbers; settings used to select power output.
GPS Global Positioning System; satellite-based long-range navigational system.
GREAT Gulf Reef Environmental Team; nonprofit diving and environmental organization.
H Hydrogen; an atomic element.
HELP Heat Escape Lessening Posture; survival position taught to submarine crews.
Hg Inches of mercury; unit of pressure measurement; 29.92 Hg is equal to 14.7 psi or 1 ATM.
HP High Pressure.
HSA Handicapped Scuba Association; scuba training organization devoted to divers with physical disabilities.
hydro Slang term for hydrostatic test; an integrity test performed on all cylinders containing compressed gas.
IAND International Association of Nitrox Divers; training and certification organization.
ICDI International Commercial Diving Institute; commercial dive training business.
ICUE International Conference of Underwater Education; annual educational conference sponsored by NAUI. (see NAUI)
IDC Instructor Development Course; class designed to teach divers how to become diving instructors.
IDEA International Diving Educators Association; certification and training organization.
IDI International Divers Incorporated; equipment manufacture.
IE Instructor Evaluation; test required by some certification agencies before becoming an instructor; term also means Instructor Evaluator, the person who administers the evaluation.
IMS Institute of Marine Sciences; research facility in Roatan, Honduras.
IP Intermediate-pressure.
ISDA International Sport Divers Association; certification and training organization.
ISEA International Scuba Educators Association, Inc. ; certification and training organization.
ISO International Standards Organization; group that has made recommendations for the manufacture of several items, including photographic film.
ITC Instructor Training Course; name of course where a certified diver learns to be a diving instructor.
K Kelvin; measurement of temperature often used in conjunction with the metric system; 492*K is equal to 0 Celsius; 0* is equal to "absolute zero"; to convert from Celsiusto Kelvin, add 273 to the Celsius reading.
KADO Keys Association of Dive Operators; organization of Florida Keys dive centers and dive boat operators.
kg/cm2 kilograms per square centimeter; measurement of pressure; 1.033 Kg/cm2 is equal to 14.7 psi or 1 ATM.
km kilometer; measurement of length.
kmh kilometers per hour; measurement of speed.
L.A. County L.A. County Department of Parks & Recreation, Underwater unit; county government training and certification organization.
LCD Liquid Crystal Diode; used in diving instrument displays.
LP Low-pressure.
LPI Low-pressure inflator; piece of diving equipment that allows a buoyancy compensator to be inflated directly from an air tank.
LS Long Shot; term used in underwater video production.
m meter; equal to 3.28 feet
MARPOL marine pollution laws; international maritime pollution regulations.
MDEA Multinational Diving Educators Association; dive certification and training organization.
MFA Medic-First Aid; basic first aid certification course offered by PADI. (see PADI)
MI Master Instructor; level of instructor certification.
min Minute; equal to 1/1,000 of a meter.
mm Millimeter; unit of distance measurement.
mm Hg Millimeter of Mercury; unit of pressure measurement; 760 mm HG is equal to 14.7 psi or 1 ATM.
MMDC Micronesian Mariculture Development Center; center for non-profit conservation programs in Micronesia.
MMII Motor Marine II underwater camera made by Sea & Sea.
MMPA Marine Mammal Protection Act; U.S. government legislation that protects marine mammals.
MOD Maximum Operating Depth; term used to indicate operational depth limitations.
MS Medium Shot; term used in underwater video production.
MSD Master Scuba Diver; level of diving certification denoting completion of a wide variety of continuing education courses.
MS-DOS Microsoft Disc Operating System; computer program, often indicates an IBM-compatible computer system.
MSDT Master Scuba Diver Training; level of instructor certification.
N Nitrogen; an atomic element.
N2 Nitrogen gas.
NA Netherlands Antilles; group of Dutch islands in the Caribbean basin.
NACD National Association of Cave Diving; organization that trains and certifies cavern and cave divers.
NASA National Aeronautics and Space Administration; U.S. space agency.
NASDS National Association of Scuba Diving Schools; certification and training organization.
NASE National Academy of Scuba Educators; certification and training organization.
NAUI National Association of Underwater Instructors; certification and training organization.
NCSRA Northern California Scuba Retailers Association.
NDL No-decompression limits; term used in association with several versions of dive tables.
NEDU Naval Experimental Diving Unit; branch of the U.S. Navy.
NEPA National Environmental Policy Act; regulation that requires impact statements be conducted for all legislative proposals or major federally licensed actions.
NIADD National Instructors Association for Divers with Disabilities; certification and training organization devoted to divers with physical disabilities.
NITROX Gas mixture containing oxygen and nitrogen.
nm Nanometers; unit of distance measurement equal to 1/1,000,000 of a meter.
NMFS National Marine Fisheries Service; government organization that oversees U.S. fishing policies.
NMRI Naval Medical Research Institute.
NNI NOAA Nitrox I; refers to a breathing gas mixture with approximately 32 percent oxygen and 68 percent nitrogen.
NNII NOAA Nitrox II; refers to a breathing gas mixture with approximately 36 percent oxygen and 64 percent nitrogen.
NOAA National Oceanic and Atmospheric Administration; a government agency that oversees a wide variety of scientific and commercial concerns related to land, water, and air.
NOS National Ocean Service; a division of NOAA. (see NOAA)
NSGA National Sporting Goods Association; organization that, among other activities tracks and surveys diving and snorkeling activity in the United States.
NSMRL Naval Submarine Medical Research Laboratories; division of the U.S. Navy.
NSS/CDS National Speliological Society, Inc. , Cave Diving Section; organization that educates and certifies cavern and cave divers.
NUADC National underwater Accident Data Center; organization that collects and disseminates information about diving accidents.
NWS National Weather Service; U.S. government organization that collects and disseminates weather-related information.
NWSS National Women's Scuba Society.
O Oxygen; an atomic element.
O2 Two oxygen atoms; usually denotes oxygen gas.
OAR Organization for Artificial Reef; environmental action association.
ORCA Outdoor Recreation Coalition of America; recreational political action organization.
OSHA Occupational Safety & Health Administration; regulatory agency.
OW Open Water; initial level of scuba certification.
OWII Openwater II; scuba certification offered by NAUI. (see NAUI)
OWSI Open Water Scuba Instructor.
P & I Protection & Indemnity Insurance Policy; type of insurance policy.
PADI Professional Association of Dive Instructors; scuba certification and training organization.
PC personal computer.
PDIC Professional Diving Instructors Corp. International; diving certification and training organization.
PFD Personal Floatation Device; a piece of equipment such as a life jacket that provides positive buoyancy. (not a buoyancy compensator)
PFO Patent Foramen Ovale; medical condition that affects the flow of blood through the heart.
PG Pressure Group; term used in conjunction with DCIEM dive tables.
PNG Papua New Guinea; island nation located at the western rim of the Pacific Ocean.
PSA Professional Scuba Association; certification and training organization.
PSD Public Service Diver; professional rescue and recovery diver.
psi Pounds Per Square Inch; unit of measurement for pressure.
PSI Professional Scuba Inspectors, Inc. ; private business that trains divers on how to inspect scuba tanks.
psia Absolute Pressure; measurement denoting total pressure often used in gas calculations; it is calculated by adding atmospheric pressure to gauge pressure; for example a tank that reads 3,000 psi at sea level has an absolute pressure of 3,014.7 psi. (3,000 psi + 14.7 psi [1 ATM] = 3,014.7 psia)
PVC polyvinyl chloride; construction material.
QR Quick Release.
R Rankin; temperature measurement sometimes used in the Imperial system; 0* R is equal to "absolute zero", 492* R is equal to 32* Fahrenheit; to convert from Fahrenheit to Rankin, add 260* to the Fahrenheit reading.
RAM Random Access memory; computer-related term.
RDP The PADI Recreational Dive Planner; a specific type of dive table.
REEF Reef Environmental Education Foundation; environmental organization.
RF Repetitive Factor; term used in DCIEM dive tables to indicate theoretical nitrogen loading in body tissues.
RNT Residual Nitrogen Time; term used in conjunction with several dive tables to indicate theoretical nitrogen loading in body tissues.
ROM Read Only Memory; computer related term.
ROV Remotely Operated Vehicle; submersible unit used for underwater exploration.
RSTC Recreational Scuba Training Council; organization of certification and training agencies that sets voluntary training standards.
SBCC Santa Barbara City College; Southern California community college offering commercial diving programs.
SCR Surface Consumption Rate; air consumption measurement.
SCRU Submerged Cultural Resources Unit; government agency responsible for research and preservation projects on select underwater archaeological areas.
SCUBA Self-contained Underwater Breathing Apparatus; term used to describe the tank/regulator system of underwater life support equipment.
SDL Skin Diving Leader; NAUI leadership certification. (see NAUI)
SDM Skin Diver magazine.
SDRG Scuba Diving Research Group; scuba division of ORCA. (see ORCA)
SEAL Sea, Air, and Land; "special operations" unit of the U.S. Navy.
SEOG Supplemental Educational Opportunity Grant; financial assistance program.
SET Simulated Empty Tank; diving procedure used in the Diamond Reef ® buoyancy training system.
SGMA Sporting Goods Manufacturers Association.
SLAM Scuba Lifesaving and Accident Management; YMCA rescue certification course.
SLR Single Lens Reflex; still camera design that allows the user to see exactly what the lens "sees".
SPG Submersible Pressure Gauge; diving instrument that measures tank pressure.
SRA Scuba Retailers Association.
SRC Submarine Rescue Chamber; rescue vehicle for submariners.
SSI Scuba Schools International; scuba certification and training agency.
STI-NAPA Bonaire Marine Park Foundation.
STP Standard Temperature and Pressure; term used to define a base-line measurement used for performance and weather calculations. (STP is equal to being at sea level on a 60* day with a barometric pressure reading of 29.92 Hg)
S-VHS Super VHS; type of video camera and videotape.
S-VHS-C Super Compact VHS; type of video camera and videotape.
TBI Total Bottom Time; term used with several dive table formats; indicates the sum of Residual Nitrogen time and Actual Bottom Time.
TED Turtle Excluder Device; device that allows turtles to escape and / or be excluded from fishing nets.
TLS Tri-laminate Material; used in dry suit construction.
TNC The Nature Conservancy; environmental organization.
TNT Total Nitrogen Time; term used in several dive table formats; equal to the sum of Residual Nitrogen Time and Actual Dive Time.
TRACOR Texas Research Electronic Analog Computer; first electronic analog decompression computer. (1963)
TTL Through The Lens; light metering system that coordinates strobe power output with camera shutter and aperture settings.
TU Tank Unit; segment of a hoseless dive computer.
TUSA Tabata USA; equipment manufacturer.
UC University of California; academic home or the Scripps Institute of Oceanography.
UDT Underwater Demolition Team; division of the U.S. Navy.
UHMS Undersea Hyperbaric Medical Society; professional medical organization devoted to diving-related issues.
UNEXSO Underwater Explorers Society; dive resort in Freeport, Bahamas.
URI Upper Respiratory Infection; illness.
USCG United States Coast Guard.
USD U.S. Divers; equipment manufacturer.
Underwater Science & Educational Resources; division of Indiana University.
USFWS United States Fish and Wildlife Service; government agency charged with designating a myriad of wildlife-related concerns, including designation of threatened and endangered species.
USNDT United States Navy Dive Tables.
USOA Underwater Society of America; umbrella organization of U.S. dive clubs.
USUF United States Underwater Federation; U.S. member of World Underwater Federation. (CMSA)
UV Ultraviolet light; refers to non-visible segment of the electromagnetic spectrum; form of radiation that causes sunburn.
UVA Ultraviolet A; segment of the UV spectrum with a wave length of 320 to 400 nm.
UVB Ultraviolet B; segment of the UV spectrum with a wave length of 190 and 320 nm.
UVC Ultraviolet C; segment of the UV spectrum with a wave length of 200 to 290 nm.
VCR Video Cassette Recorder.
VHS Video Home System; format standards of video cassettes, recorders and cameras.
VHS-C Compact VHS; type of video camera and video tape.
VIP Visual Inspection Program; term used for a variety of scuba inspections but most often for the visual inspection of a scuba tank.
VIVA Venturi Initiated Vacuum Assist; second-stage regulator design that reduces amount of inhalation pressure required to draw air from the first-stage.
WSA Washington Scuba Alliance; dive organization in Washington state.
WSA Women's Scuba Association; women's scuba organization.
WSI Water Safety Instructor; American Red Cross swimming instructor certification.
WU Wrist Unit; segment of a hoseless dive computer.
YMCA Young Men's Christian Association; organization that, among other activities, provides scuba certification and training.
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