TRIENNIAL


Meaning of TRIENNIAL in English

/ traɪˈeniəl; NAmE / adjective

happening every three years

••

WORD ORIGIN

mid 16th cent.: from late Latin triennis (from Latin tri- three + annus year) + -al .

Oxford Advanced Learner's English Dictionary.      Оксфордский английский словарь для изучающик язык на продвинутом уровне.