'apotelesm' originates from Greek, specifically the word 'apotelesma', where 'apo-' meant 'away/from' and 'telein' (root of 'teles-') meant 'to finish, accomplish'.

'apotelesm' changed from the Greek word 'apotelesma' into Late Latin/Medieval Latin 'apotelesma' and entered English usage as a learned/technical noun (seen in writings on astrology and theology).

Initially it meant 'that which accomplishes or the result of an action'; over time it has been used more generally as 'result' or specifically as 'astrological effect'.