Triennial(a.) Continuing three years; as, triennial parliaments; a triennial reign.
Triennial(a.) Happening, coming about, or appearing once in every three years; as, triennial elections; a triennial catalogue; a triennial visitation.
Triennial(n.) Something which takes place or appears once in three years.
Triennially(adv.) Once in three years.
Words within trienniality