'isopetalous' originates from Greek, specifically the elements 'iso-' and 'petalon', where 'iso-' meant 'equal' and 'petalon' meant 'leaf' or 'thin plate' (used for 'petal').

'isopetalous' was formed in New Latin/modern botanical usage from the Greek elements 'isos' and 'petalon' and entered English as a technical botanical adjective in recent centuries.

Initially built from elements meaning 'equal' + 'leaf/plate', it came to be used specifically in botany to mean 'having equal petals'.