'archaise' originates from Modern English, formed by combining the adjective 'archaic' with the verb-forming suffix '-ize' (from Greek '-izein' via Latin/French), ultimately from Greek 'arkhaîos' meaning 'ancient'.

'archaise' developed as a variant spelling of 'archaize' (the -ise spelling reflecting British orthography). The formation comes from 'archaic' + '-ize', with roots in Greek 'arkhaîos' and Late Latin/French intermediaries before entering English.

Initially it meant 'to make ancient or to render in an old style'; over time the meaning has remained substantially the same, used chiefly to denote intentional adoption of archaic forms or style.