To scuba dive.
1.a brand of underwater breathing apparatus for a swimmer or skin-diver, consisting of a cylinder of compressed air that is strapped to the back, a flexible tube connecting the cylinder with the swimmer's mouth, and an automatic pressure regulator that controls the flow of air into the lungs.
1. breathing apparatus used by divers, etc, consisting of a mouthpiece attached to air cylinders strapped to the back Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollinsPublishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012 Cite This Source
1950, from aqua- + lung. Developed 1943 by Jacques Cousteau and Emile Gagnan.
Learn More about aqualung