tercentenary
ter·cen·te·nary
noun
1.
the 300th anniversary (or the celebration of it)
Origin
From ter- + centenary, after Latin ter centēnī (“three hundred each”).
Related words
Broader terms
WordNet 2.1 (Princeton University). Wiktionary (CC BY-SA). WordNet 2.1 Copyright Princeton University. All rights reserved. Wiktionary content is available under the Creative Commons Attribution-ShareAlike Licence.