'isocotyly' originates from New Latin/modern scientific formation, combining Greek elements: 'iso-' from Greek 'isos' meaning 'equal' and 'cotyl' from Greek 'kotyle' (via 'cotyledon') meaning 'cup' or 'hollow' (used for 'seed leaf').

'isocotyly' was formed in botanical English from the combining form 'iso-' + element from 'cotyledon' (from Greek 'kotyledon') with the noun-forming suffix '-y', producing a technical term in New Latin and modern botany.

Initially and throughout its use it has meant 'having equal cotyledons'; the technical meaning has been largely stable.