The term 'big-leaved' is a compound adjective formed from 'big' and 'leaved', where 'big' originates from Old English 'bīg' meaning 'large' and 'leaved' is derived from 'leaf', which comes from Old English 'lēaf'.

'Big-leaved' evolved from the combination of 'big' and 'leaved', which were used separately in Old English and later combined in modern English to describe plants with large leaves.

Initially, 'big' meant 'large in size' and 'leaved' referred to having leaves. The combination has retained its meaning of describing plants with large leaves.