'atopic' originates from Greek, specifically the word 'atopos', where 'a-' meant 'not' and 'topos' meant 'place'. The English medical noun 'atopy' was coined in the early 20th century from this root, and the adjective 'atopic' was formed from 'atopy' with the suffix '-ic'.

'atopic' changed from the medical noun 'atopy' (coined in English in the early 20th century from Greek 'atopia'/'atopos') and eventually became the modern English adjective 'atopic' used especially in medical contexts.

Initially, the Greek root meant 'out of place' or 'strange'; over time the term evolved into a medical sense meaning 'pertaining to atopy'—a predisposition to allergic hypersensitivity—rather than its original sense of 'out of place'.