| Acronym | Meaning |
| SAA | Sub-Aqua Association |
| PADI | Professional Association Of Diving Instructors |
| ADT | Actual Dive Time |
| BHA | British Hyperbaric Association |
| SCUBA | Self Contained Underwater Breathing Aparatus |
| EFR | Emergency First Response |
| DV | Demand Valve |
| IDEA | International Diving Educators Association; Diving Instruction Organization. |
| RYA | Royal Yachting Association |
| AD | Adventure Diver (PADI) Advanced Diver (BSAC) |