'angled-veined' is a compound formed from the English adjective 'angled' (from 'angle') and the past-participial adjective 'veined' (from 'vein'); 'angle' ultimately comes from Latin 'angulus' meaning 'corner', and 'vein' comes from Latin 'vena' meaning 'vein' or 'blood-vessel'.

'angle' developed via Old French and Middle English from Latin 'angulus', and 'vein' passed from Latin 'vena' into Old French 'veine' before entering Middle English; the descriptive compound 'angled-veined' arose in modern English botanical and descriptive usage by combining these existing adjective forms.

Initially, the separate roots referred to 'corner' (angle) and 'blood vessel/vein' (vena); over time the combined descriptive use came to mean 'having veins that form angles' specifically in botanical or anatomical description.