The Collaborative International Dictionary
Quadrennium
Quadrennium \Quad*ren"ni*um\, n. [NL. See Quadrennial.] A space or period of four years.
Wiktionary
quadrennium
n. a period of four years
Wikipedia
Quadrennium
A quadrennium (pl. quadrennia or quadrenniums) is a period of 4 years, most commonly used in reference to the 4-year period between each Olympic Games. Also used in reference to the 4 year interval between leap years, for example when wishing friends and family a "Happy quadrennium" on February 29.
Category:Units of time