'flask-like' originates from English, specifically the compound of 'flask' and the suffix '-like', where 'flask' meant 'a bottle' and '-like' meant 'having the form or nature of'.

'flask' entered English via Middle English 'flaske' from Old French 'flasque' (from Medieval Latin 'flasco'); the suffix '-like' comes from Old English 'līc'/'-lic' (Proto-Germanic *likaz) meaning 'similar', and these elements combined in Modern English to form compounds such as 'flask-like'.

Initially it meant 'having the form of a flask', and over time it has retained this basic meaning as an adjective describing shape or resemblance.