QUINQUENNIAL Meaning of QUINQUENNIAL in English [ kwɪŋ'kwɛnɪəl ]■ adjective lasting for or recurring every five years.Derivatives~ly adverb OriginC15: from L. quinquennis (from quinque 'five' + annus 'year') + -al . Concise Oxford English vocab. Сжатый оксфордский словарь английского языка. 2004