Scuba diving
underwater diving where the diver breathes from apparatus (scuba) which is completely independent of surface supply / From Wikipedia, the free encyclopedia
Scuba diving is an activity where people (called "scuba divers", or simply "divers") can swim underwater. They can be underwater a long time by having a tank filled with compressed air. The tank is a large metal cylinder made of steel or aluminum.
The word scuba is an acronym from "Self-Contained Underwater Breathing Apparatus".