'spirometer' originates from Neo-Latin/International scientific vocabulary, specifically the combining form 'spiro-' from Latin 'spirare' meaning 'to breathe' and the suffix '-meter' from Greek 'metron' meaning 'measure'.

'spirometer' was formed in scientific/medical usage by combining 'spiro-' + '-meter' (from Latin and Greek roots) in the 19th century and eventually entered modern English as 'spirometer'.

Initially, the term meant 'an instrument for measuring breath'; over time it has remained essentially the same, referring specifically to devices that measure lung volumes and capacities.