What does triennial mean?
Triennial is an adjective and noun meaning that something occurs every three years or lasts for three years. Its adjectival use is especially common in formal, institutional contexts, as in triennial reports, reviews, conferences, and planning cycles. The noun refers to an event or celebration that takes place on a three-year schedule. Although the word can sometimes suggest lasting for three years, its dominant modern meaning concerns a regular three-year interval. Triennial is related in structure and origin to words such as biennial, centennial, perennial, and quadrennial, which likewise combine a Latin numeral with the word for year. It is particularly useful when discussing recurring civic, cultural, scientific, or organizational activities that follow a three-year schedule, while remaining distinct from annual, biennial, and other frequency terms.
Occurring or recurring every three years; lasting for three years.
"The committee approved a triennial assessment of the program."
The every-three-years sense is more common today than the sense lasting for three years.
An event, period, or celebration occurring every three years.
"The biennial exhibition is accompanied by a smaller triennial festival."
As a noun, triennial is usually used with a term such as conference, review, report, or celebration.
The plural is used when referring to more than one recurring event or occasion of this kind.
"The two triennials attracted different professional audiences."
Triennial packs a three-year rhythm into its very name: its Latin roots mean three and year.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does triennial come from?
Triennial comes from Latin triennis, meaning “of or lasting three years,” formed from tres, “three,” and annus, “year.” The word entered English in the seventeenth century and was initially associated with a three-year period or a three-year cycle. Its English relatives biennial, centennial, perennial, and quadrennial share the same Latin year element and combine it with different numerical prefixes.
Related word forms
How triennial is actually used
Usually formal or institutional in tone. As a noun, triennial most often refers to a recurring event, especially a conference, review, celebration, or cycle.
Easily confused with triennial
Both words can refer to recurring events, but triennial means every three years, whereas biennial means every two years and can also mean lasting two years.