'rapturous' ultimately comes from the noun 'rapture' + the adjectival suffix '-ous'; 'rapture' entered English from Old French and Medieval Latin 'raptura' (from Latin 'raptus').

'rapture' derives from Latin 'raptura' (past participle related to 'rapere' meaning 'to seize' or 'carry off'); English 'rapture' passed through Old French/Medieval Latin forms and later produced the adjective 'rapturous'.

Originally associated with being 'seized' or 'carried away' (physically or emotionally), the sense shifted toward 'being carried away with intense delight or ecstasy', giving the modern meaning of strong joy or enthusiasm.