'sympetalous' originates from New Latin, formed from Greek elements 'sym-' (from Greek 'syn-') meaning 'together' and 'petalon' meaning 'leaf' or 'petal', plus the English adjectival suffix '-ous'.

'sympetalous' developed via botanical/Latin formations such as New Latin 'sympetalus' (from Greek 'syn' + 'petalon') and entered English usage in botanical contexts, particularly in the 19th century.

Initially it described petals joined together in botanical descriptions; over time the meaning has remained essentially the same and is still used to denote fused petals of a corolla.