Wiktionary
tricentennial
a. Occurring every three-hundred (300) years. n. The 300th anniversary of an event or happening.
WordNet
tricentennial
adj. of or relating to or completing a period of 300 years [syn: tricentenary]
Usage examples of "tricentennial".
Kirk of Starfleet Command, and we'll be talking today about this summer's Apollo Tricentennial and Starfleet's role in the celebrations.