Synonyms/Hypernyms (Ordered by Estimated Frequency) of noun triennial

1 sense of triennial

Sense 1
tercentennial, tercentenary, triennial -- (the 300th anniversary (or the celebration of it))
       => anniversary, day of remembrance -- (the date on which an event occurred in some previous year (or the celebration of it))

Antonyms of adj triennial

1 sense of triennial

Sense 1
triennial -- (occurring every third year or lasting 3 years)

INDIRECT (VIA periodic) -> aperiodic, nonperiodic -- (not recurring at regular intervals)

Similarity of adj triennial

1 sense of triennial

Sense 1
triennial -- (occurring every third year or lasting 3 years)
       => periodic (vs. aperiodic), periodical -- (happening or recurring at regular intervals; "the periodic appearance of the seventeen-year locust")