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.
© Webster 1913.