'apetalae' originates from Greek via New Latin, specifically from the Greek elements 'a-' and 'petalon' where 'a-' meant 'without' and 'petalon' meant 'petal'.

'apetalae' entered botanical usage as a Latinized plural in New Latin (botanical Latin) to denote groups of plants without petals; it was adopted into English botanical vocabulary from that usage in the 18th–19th centuries.

Initially, the elements meant simply 'without a petal'; over time the term came to be used as a collective noun in taxonomy to denote 'plants lacking petals' (a classification or grouping).