triennial

adjective

tri·​en·​ni·​al (ˌ)trī-ˈe-nē-əl 

1

: occurring or being done every three years

the triennial convention

2

: consisting of or lasting for three years

a triennial contract

triennial noun

triennially

(ˌ)trī-ˈe-nē-ə-lē 

adverb

Examples of triennial in a Sentence

Recent Examples on the Web

While the triennial tournament was underway, however, some new faces and non-roster invitees had a chance to shine in Red Sox camp. — Gabrielle Starr, Boston Herald, 21 Mar. 2026

Organizing a triennial today means navigating the tension between the local and the global amid a rapidly shifting world order. — Wassan Al-Khudhairi, Artforum, 2 Apr. 2026

The triennial Roppongi Crossing series, a survey of contemporary art in Japan, is unmissable for those who want to understand the local scene. — Jessica Kozuka, Travel + Leisure, 13 Mar. 2026

The Minnesota Department of Health on Tuesday released the results of the triennial survey of the state’s fifth, eighth, ninth and 11th grade students. — Dené K. Dryden, Twin Cities, 10 Dec. 2025

Word History

First Known Use

1562, in the meaning defined at sense 1

Rhymes for triennial

• bicentennial
• biennial
• centennial
• decennial
• millennial
• perennial
• quadrennial
• quinquennial
• sesquicentennial

Kids Definition

triennial

adjective

tri·​en·​ni·​al (ˈ)trī-ˈen-ē-əl 

1

: consisting of or lasting for three years

2

: occurring or being done every three years

triennial noun

triennially

-ē-ə-lē 

adverb