'atypically' originates from the prefix 'a-' meaning 'not' and the word 'typical', which comes from the Greek word 'typos', meaning 'impression' or 'model'.

'atypical' evolved from the Greek word 'atypikos', which was adopted into English in the 19th century.

Initially, it meant 'not conforming to a type', and this meaning has largely remained the same in modern usage.