EPACT Meaning of EPACT in English [ 'i:pakt ]■ noun the number of days by which the solar year exceeds the lunar year.OriginC16: from Fr. épacte , via late L. from Gk epaktai (hēmerai) 'intercalated (days)'. Concise Oxford English vocab. Сжатый оксфордский словарь английского языка. 2004