'atopy' originates from Greek, specifically the word 'atopos', where 'a-' meant 'not' and 'topos' meant 'place'.

'atopy' was formed from the Greek root via New Latin/medical coinage 'atopia' and was adopted into modern English in the early 20th century with the sense applied to a peculiar (out-of-place) immune disposition.

Initially, it meant 'strangeness' or 'peculiarity', but over time it evolved into its current medical meaning of 'a predisposition to allergic hypersensitivity'.