'apriorism' originates from Latin, specifically the phrase 'a priori', where 'a' meant 'from' and 'priori' meant 'earlier' (former), combined with the suffix '-ism' meaning 'doctrine or belief'.

'a priori' was used in classical and medieval Latin to mean 'from the earlier'; the phrase entered philosophical usage in European languages and, in English, produced the derivative noun 'apriorism' to denote the doctrine based on a priori reasoning.

Initially, the components meant 'from the earlier' (a temporal or logical priority), but over time the combined term came to denote the doctrine that certain knowledge or justification is independent of experience.