'vasodilative' originates from New Latin/modern coinage combining the prefix 'vaso-' (from Latin 'vās') and the adjective-forming element from Latin 'dilatare' + English suffix '-ive'; 'vās' meant 'vessel' and 'dilatare' meant 'to spread out or expand'.

'vasodilative' developed as a modern English medical formation from 'vasodilation' (formed from 'vaso-' + Latin 'dilat-'/'dilatare') and the adjectival suffix '-ive', so the element for 'expand' moved from the verb 'dilate'/'dilat-' into the adjective 'vasodilative'.

Initially, the component roots referred literally to 'vessel' and 'to spread/expand'; over time this combination became a technical adjective meaning 'causing the widening of blood vessels' in medical contexts.