'vasoactive' originates from the combining form 'vaso-' (from Latin 'vas', genitive 'vasis', meaning 'vessel') and the English word 'active' (derived from Latin 'activus', meaning 'active').

'vaso-' entered English via New Latin as a combining form meaning 'vessel', and it was combined with 'active' in modern medical English (20th century) to coin 'vasoactive' for agents affecting blood vessels.

Initially it meant 'acting on blood vessels', and this core meaning has been retained in current medical usage to describe substances or actions that alter vascular tone.