Learning
Scuba
Underwater diving with a self-contained breathing-gas supply.
Explore related lessons →PLAIN WORDS FOR AN UNDERWATER WORLD
The diving glossary.
From buoyancy to buddy briefings: 103 terms to help you understand what you’re reading, hearing and learning.
15 definitionsIntroductory edition · Review pending
Ocean care
Seagrass
A flowering plant adapted to living submerged in marine water.
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Second stage
The regulator component from which the diver breathes, supplying gas on inhalation in a demand system.
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Servicing
Inspection and maintenance carried out according to the equipment maker’s requirements by an appropriate service provider.
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Shore dive
A dive accessed from land rather than a boat.
Explore related lessons →Diving together
Situational awareness
Attention to relevant people, equipment and environmental changes around an activity.
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Slack water
A period of little tidal current; its local timing is not automatically the time of high or low tide.
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Slate
A surface designed for writing notes underwater with a suitable writing tool.
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Snorkel
A breathing tube used with its upper opening above water; it does not supply gas at depth.
Explore related lessons →Underwater science
Sound
Mechanical vibrations travelling through a medium such as air or water.
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SPG
Submersible pressure gauge: an instrument that indicates cylinder pressure.
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Supervision
Oversight under the arrangements of a particular course or activity; its form and scope should be clarified.
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Surface interval
Time spent at the surface between dives.
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Surface marker
A visible surface signalling device. Different designs and deployment methods need appropriate training.
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Swell
Waves that have travelled beyond the area where they were generated.
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