'vasotonic' originates from the combining form 'vaso-' (from Latin 'vas' meaning 'vessel') and 'tonic' (from Greek 'tonikos', from 'tonos' meaning 'stretch, tension').

'vasotonic' was formed in modern medical/technical English by combining the prefix 'vaso-' (from Latin 'vas') with the adjective 'tonic' (from Greek 'tonos'); the compound emerged in the 19th–20th century in physiological and pharmacological contexts.

Initially used to denote relation to vessel tone (literally 'vessel + tonic'); it has remained consistent in meaning, referring specifically to agents or effects that increase vascular tone or cause vasoconstriction.