\Quad*ren"ni*al\, a. [L. quadriennium a space of
four years; quattuor four + annus year; cf. L. quadriennis.
See {Quadrate}, and {Annual}.]
1. Comprising four years; as, a quadrennial period.

2. Occurring once in four years, or at the end of every four
   years; as, quadrennial games.