'isocotylous' originates from Greek roots via New Latin: 'iso-' (Greek 'isos') meaning 'equal' and 'cotyl-' from Greek 'kotylē' meaning 'cup' or 'small cavity' (used in botany for 'cotyledon').

'isocotylous' was formed in New Latin/modern botanical Latin from Greek elements (iso- + cotylē) and entered English usage in botanical descriptions as 'isocotylous' without major phonetic change.

Initially coined to describe the condition 'having equal cotyledons' in botanical contexts, the term has retained that technical meaning in modern usage.