Scuba & Nitrox Glossary: E
Nitrox and breathing-gas terminology is prioritized first. General scuba terms follow below. Definitions are educational summaries and do not replace formal training, manufacturer instructions, or an operational dive plan.
Nitrox & Gas Terms — E
- EAN
- Enriched Air Nitrox.
- EANx
- Enriched Air Nitrox, with “x” sometimes replaced by the oxygen percentage, such as EAN32.
- Enriched Air
- Breathing gas containing more oxygen than ordinary air; in recreational diving this generally means Nitrox.
- Equivalent Air Depth (EAD)
- The air depth that produces approximately the same nitrogen partial pressure as a given Nitrox mix at the actual depth.
- Enrichment
- Adding oxygen or removing nitrogen to create a Nitrox mixture.
- Exposure Limit
- A chosen maximum duration or dose for a gas-related hazard such as oxygen exposure.
- EAN28
- An enriched-air mixture containing approximately 28 percent oxygen.
- EAN30
- An enriched-air mixture containing approximately 30 percent oxygen.
- EAN34
- An enriched-air mixture containing approximately 34 percent oxygen.
- EAN40
- An enriched-air mixture containing approximately 40 percent oxygen.
- Exposure Limit Table
- A table relating oxygen partial pressure to recommended maximum exposure duration.
General Scuba Terms — E
- Equalization
- Balancing pressure in air spaces such as the middle ears and mask.
- Exposure Suit
- A wetsuit, drysuit, or other garment used for thermal and environmental protection.
- Emergency Action Plan
- A documented response plan for foreseeable diving emergencies.
- Entry
- The method used to enter the water, such as giant stride, seated entry, or shore entry.
- Exhalation
- Breathing out; continuous normal breathing is essential during scuba ascent.
- Ear Clearing
- Equalizing pressure in the middle ear during depth changes.
- Written Emergency Action Plan
- Documented procedures, contacts, equipment, and roles for managing dive emergencies.
- Entry Point
- The planned location where divers enter the water.
- Environmental Protection
- Practices that reduce damage to reefs, wildlife, and dive sites.
- Exit Point
- The planned or alternate location where divers leave the water.