A priori.
Etymology: [L. a (ab) + prior former.]
1. (Logic)
Characterizing that kind of reasoning which deduces consequences from definitions formed, or principles assumed, or which infers effects from causes previously known; deductive or deductively. The reverse of a posteriori.
3. (Philos.)
Applied to knowledge and conceptions assumed, or presupposed, as prior to experience, in order to make experience rational or possible. A priori, that is, form these necessities of the mind or forms of thinking, which, though first revealed to us by experience, must yet have preëxisted in order to make experience possible. Coleridge.
Shades of meaning
Fernald has no entry of its own for a priori; he lists it under transcendental.
Where he writes about it:
"Transcendent he [Kant] employed to denote what is wholly beyond experience, being neither given as an a posteriori nor a priori element of cognition--what therefore transcends every category of thought." K.-F. — from transcendental
Antonyms
none given