Full Idea
Kant defines apriority in terms of independence from genesis and from sense experience, and it is indicated by its necessity and by it generality or universality.
Gist of Idea
The apriori is independent of its sources, and marked by necessity and generality
Source
report of Immanuel Kant (Critique of Pure Reason [1781], B003-4) by Tyler Burge - Frege on Apriority (with ps) 2
Book Reference
Burge,Tyler: 'Truth, Thought, Reason (on Frege)' [OUP 2001], p.367