'perspiratory' originates from Latin, specifically the word 'perspirare', where 'per-' meant 'through' and 'spirare' meant 'to breathe'.

'perspiratory' developed from the verb 'perspire' (from Latin 'perspirare') and was formed in English with the adjective-forming suffix '-atory' to yield 'perspiratory'.

Initially it related to the idea of 'breathing through' or 'exhaling moisture', but over time it evolved to the modern sense of 'relating to sweating' or 'producing/exuding sweat'.