'aptitudinally' originates from Latin, specifically the word 'aptitudo', where 'apt-' meant 'fit' or 'suitable'; it entered English via the noun 'aptitude' plus the adjectival suffix '-al' and the adverbial suffix '-ly'.

'aptitudinally' changed from the Latin 'aptitudo' into French/Medieval Latin 'aptitude', then into Middle English 'aptitude', later forming the adjective 'aptitudinal' and finally the adverb 'aptitudinally'.

Initially the root meant 'fitness' or 'suitability'; over time the sense shifted toward 'natural ability or talent' (aptitude), and the adverb came to mean 'in a manner related to aptitude'.