'spirometer' originates from New Latin/modern scientific coinage, specifically from the combining element 'spiro-' (from Latin 'spirare') meaning 'to breathe' and the suffix '-meter' from Greek 'metron' meaning 'measure'.

'spirometer' was formed in New Latin/scientific English from 'spiro-' + '-meter' (compare New Latin 'spirometria'/'spirometrum') and eventually became the modern English word 'spirometer' (with the spelling variant 'spirometre').

Initially, the term referred to a device for measuring breathing (lung volumes), and over time it has retained that specific medical/technical meaning.