SeaLogScuba Diving Glossary
176 diving terms explained in plain English, from your first pool session to technical decompression dives. Gear, physics, physiology, training, conditions, and the words you only ever hear on a dive boat. Every term links to related concepts, so you can follow the thread as deep as you like.
Gear & Equipment
Every piece of scuba gear explained, from the BCD and regulator to backplates, reels, and reef hooks.
- Backplate and Wing
- BCD (Buoyancy Control Device)
- Dive Compass
- Dive Computer
- Dive Knife
- Dive Light
- Dive Mask
- Drysuit
- DSMB (Delayed Surface Marker Buoy)
- Fins
- First Stage
- Hood
- Lift Bag
- Manifold
- Octopus
- Pony Bottle
- Rebreather
- Reef Hook
- Reel and Spool
- Regulator
- Scuba Tank
- Second Stage
- Snorkel
- SPG (Submersible Pressure Gauge)
- Stage Bottle
- Tank Valve
- Weight System
- Wetsuit
Dive Physics
The gas laws and pressure concepts behind everything that happens to you and your gear underwater.
Physiology & Dive Medicine
How diving affects the body: equalization, narcosis, decompression sickness, and other conditions every diver should understand.
- Arterial Gas Embolism (AGE)
- Barotrauma
- Decompression Illness (DCI)
- Decompression Sickness (DCS)
- Dehydration and Diving
- Equalization
- Frenzel Maneuver
- Hypercapnia
- Hypothermia
- Hypoxia
- Lung Overexpansion Injury
- Mask Squeeze
- Nitrogen Narcosis
- Off-Gassing
- Oxygen Toxicity
- Residual Nitrogen
- Reverse Block
- Seasickness
- Valsalva Maneuver
Skills & Techniques
The in-water skills taught from Open Water to tech: buoyancy, trim, kicks, entries, and emergency drills.
Training & Certification
Certification agencies and course levels, from Discover Scuba to Divemaster and beyond.
- Advanced Open Water Diver
- BSAC (British Sub-Aqua Club)
- C-card
- Certification Agency
- Check Dive
- CMAS (Confédération Mondiale des Activités Subaquatiques)
- Discover Scuba Diving
- Dive Instructor
- Divemaster
- GUE (Global Underwater Explorers)
- NAUI (National Association of Underwater Instructors)
- Open Water Diver
- PADI (Professional Association of Diving Instructors)
- Refresher Course
- Rescue Diver
- SSI (Scuba Schools International)
Gas Mixes & Technical Diving
Nitrox, trimix, gas planning, and the decompression theory vocabulary of technical diving.
Ocean & Conditions
Currents, thermoclines, visibility, and the underwater terrain divers explore.
Types of Diving
From shore dives and liveaboards to wrecks, caves, ice, and blue water.
Safety & Procedures
The procedures, stops, and emergency protocols that keep divers safe.
Dive Planning & Navigation
Planning terms every diver logs: profiles, bottom time, surface intervals, and navigation.