a priori /ˌɑː pɹiˈɔːɹi/adjective 4adverb 1forms 2 adjective4 •Presumed without analysis. •Based on hypothesis and theory rather than experiment or empirical evidence.In his opening argument, the student mentioned nothing beyond his a priori knowledge. •Self-evident, intuitively obvious. •Developed entirely from scratch, without deriving it from existing languages. adverb1 •In a way based on theoretical deduction rather than empirical observation. formsmore a priori · most a priori