I. adjective relating to or denoting reasoning or knowledge which proceeds from theoretical deduction rather than from observation or experience • a priori assumptions about human nature.
II. adverb in a way based on theoretical deduction rather than empirical observation • sexuality may be a factor but it cannot be assumed a priori.
III. derivatives apriorism /eɪˈprʌɪəˌrɪz(ə)m / noun
– origin late 16th cent.: Latin, ‘from what is before’.