'apnea' originates from Greek, specifically the word 'apnoia', where 'a-' meant 'without' and 'pnoe' meant 'breath'.

'apnoia' passed into scientific/medical Latin and later into modern English as 'apnea' (American spelling) and 'apnoea' (British spelling).

Initially, it meant 'without breath' in a literal sense; over time it evolved into the medical term referring to episodes of stopped breathing, especially during sleep.