'compound-leaved' is formed by combining the adjective 'compound' (ultimately from Latin 'componere' meaning 'to put together') with the noun 'leaf' (Old English 'lǣaf') plus the adjectival suffix '-ed'.

'compound' came into English via Old French and Middle English from Latin 'componere' (com- 'together' + ponere 'to place'), while 'leaf' comes from Old English 'lǣaf' (from Proto-Germanic *laubą). The modern compound adjective 'compound-leaved' is a descriptive formation in Modern English, created by joining these elements with '-ed' to mean 'having leaves of a compound form'.

Originally 'compound' meant 'made up of parts' and 'leaf' simply referred to the foliage. Over time the combined form came to have the specific botanical sense 'having leaves composed of multiple leaflets.'