Aqua-Lung

or Aq·ua Lung

[ ak-wuh-luhng, ah-kwuh- ]
/ ˈæk wəˌlʌŋ, ˈɑ kwə- /

Trademark.

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.