The epact (from Greek: epaktai hèmerai = added days) is, as the second Canon of the Gregorian calendar reform puts it, "nothing else than the number of days by which the common solar year of 365 days surpasses the common lunar year of 354 days" (Latin: Epacta nihil aliud est quam numerus dierum quibus annus solaris communis dierum 365 annum communem lunarem dierum 354 superat).