physics - Aqualung

An aqua-lung (often spelt aqualung in Britain) is a type of SCUBA diving equipment consisting of a high pressure diving cylinder and a diving regulator that supplies the diver with breathing gas at ambient pressure.
Aqualung is a concept album by the rock band Jethro Tull, as well as a hit song from that album.
Aqualung is the stage name of Matt Hales, a British musician.
Aqualung is a concert venue in the Spanish city of Madrid.