Home › Words › T › trienniumtriennium/traɪˈɛniəm/triennium · noun — A period of three years.Definition from Wiktionary (CC BY-SA 3.0).triennium is pronounced /traɪˈɛniəm/.EtymologyFrom Latin triennium, from triennis (“3-year”) + -ium (suffix forming abstract nouns).nounA period of three years.Definitions & examples from Wiktionary (CC BY-SA 3.0).Words closest in meaningBy meaning, not spelling — each word's AI semantic fingerprint, nearest first.trieterical 75% match — Triennial: occurring once in three years. vs triennium →triennially 74% match — Occurring at intervals three years apart. vs triennium →trieteric 74% match — Synonym of triennal (“related to or characterized by an three-year period”) vs triennium →triyearly 72% match — Three times in a year. vs triennium →tricennial 71% match — Of, related to, lasting, or occurring once every thirty years. vs triennium →trimonthly 69% match — Occurring at intervals three months apart. vs triennium →trillennial 68% match — Pertaining to an age or duration of 3,000 years. vs triennium →trigintennial 67% match — Synonym of tricennial, once every thirty years. vs triennium →