'aqualung' originates from English, specifically the compound of Latin 'aqua' and English 'lung', where 'aqua' meant 'water' and 'lung' meant the breathing organ.

'Aqua-Lung' was coined and used as a trademark in the 1940s for the breathing apparatus developed by Émile Gagnan and Jacques-Yves Cousteau; the hyphenated trademark later became the generic English word 'aqualung'.

Initially, it referred specifically to the trademarked breathing apparatus; over time it evolved into a general term for self-contained underwater breathing equipment and also became a cultural reference (e.g., album title).