'non-fused-leaved' originates from English, formed by the prefix 'non-' (from Latin 'non' meaning 'not'), the past participle 'fused' (from Latin 'fundere' via Old French meaning 'to join/pour/merge'), and 'leaf' from Old English 'lǣf' meaning 'leaf'.

'non-' is a negative prefix from Latin; 'fuse' developed from Latin 'fundere' into Old French and Middle English forms ('fusen'/'fusen') and became English 'fuse'; 'leaf' comes from Old English 'lǣf' and evolved into modern English 'leaf'; the compound 'non-fused-leaved' is a modern English descriptive compound created by combining these elements for specialized botanical description.

Initially the components meant 'not' + 'joined/merged' + 'leaf', and together they have been used in modern botanical contexts to mean 'having leaves that are not joined'; this specialized descriptive meaning has remained consistent.