A pri-ō'rī

[Lat. prior, former, compar., superl. primus.]

1Sense 1. (Logic.) Reasoning a priori is that which deduces consequences from definitions formed, or principles assumed, or which infers effects from causes previously known. This is the reverse of a posteriori.

2Sense 2. (Philos.) Knowledge and conceptions a priori are assumed, or pre-supposed, as prior to experience, in order to make experience rational or possible.

A priori, that is, from these necessities of the mind or forms of thinking, which, though first revealed to us by experience, must yet have pre-existed in order to make experience possible. (Coleridge.)