HDS: Historical Diving Society
HEPCA: Hurghada Environmental Protection and Conservation Association
HID: High Intensity Discharge
HP: High Pressure
HPNS: High Pressure Nervous Syndrome
HSA: Handicapped Scuba Association
HSE: Health and Safety Executive
IAHD: International Association for Handicapped Divers
IAND: International Association of Nitrox Divers
IANTD: International Association of Nitrox and Technical Divers
IDC: Instructor Development Course
IDEA: International Diving Educators Association
IDEST: Inspectorate for Diving Equipment Servicing and Testing
IOC: Instructor Orientation Course
IP: intermediate pressure
ISO: International Standards Organisation
ITC: Instructor Training Course
ITS: Instructor Training Scheme
ITW: Instructor Training Workshop
IUC: Irish Underwater Council
JAMA: Journal of the American Medical Association
KISS: Keep It Simple, Stupid
LAT: Lowest Astronomical Tide
LDS: Local Dive Shop
LIDS: London International Dive Show
LP: Low Pressure
MCA: Maritime and Coastguard Agency
MCS: Marine Conservation Society
MDEA: Multinational Diving Educators Association
MDT: Maximum Dive Time
MFW: Metres of Fresh Water
MGR: Mixed Gas Rebreather
MKS: metre, kilogram, second
MOD: Maximum Operating Depth
MSD: Master Scuba Diver
MSDT: Master Scuba Diver Trainer
MSW: Metres of Salt Water
NABS: National Association of Black Scuba Divers
NACD: National Association for Cave Diving
NACDS: National Association of Commercial Diving Specialists