a device (trade name Aqua-Lung) that lets divers breathe under water; scuba is an acronym for self-contained underwater breathing apparatus, A portable apparatus having a container with compressed air, a regulator that is equipped with a mouthpiece and adjusts the pressure of the released air to match the surrounding pressure, and often a buoyancy compensator, used for breathing under water, An apparatus carried by a diver, which includes a tank holding a mixture of oxygen and other gases, used for breathing underwater, verb_ rare To perform scuba diving