| Acronym | Meaning |
| MCS | Marine Conservation Society |
| ITS | Instructor Training Scheme (BSAC) |
| TNT | Total Nitrogen Time |
| DAN | Divers Alert Network |
| OWI | Open Water Instructor (BSAC) |
| AD | Adventure Diver (PADI) Advanced Diver (BSAC) |
| AOW | Advanced Open Water |
| ITW | Instructor Training Workshop (BSAC) |
| EAN(X) | Enriched Air Nitrox |
| DCS | Decompression Sickness |