[epact] n [MF epacte, fr. LL epacta, fr. Gk epakte, fr. epagein to bring in, intercalate, fr. epi- + agein to drive--more at agent] (1588): a period added to harmonize the lunar with the solar calendar
EPACT
Meaning of EPACT in English
Merriam-Webster English vocab. Английский словарь Merriam Webster. 2012