from
The Collaborative International Dictionary of English v.0.48
Self-contained Underwater Breathing Apparatus \Self`-con*tained"
Underwater Breathing Apparatus\, n.
A portable device to allow divers to breathe while under
water, consisting of one or two tanks of compressed air which
are strapped onto the back of the diver, and are connected by
tubing to a mouthpiece through which the diver receives the
air from the tanks at rate adjustable by a valve; -- called
also {SCUBA}, {SCUBA gear}, or {SCUBA apparatus}.
[PJC]