. For yet more, epoch.A millennium (pl. millennia) is a period of time equal to one thousand years (from Latin , thousand, and , year). The term may implicitly refer to calendar millennia; periods tied numerically to a particular dating system, specifically ones that begin at the starting (initial reference) point of the calendar in question (typically the year 1) or in later years which are whole number multiples of a thousand years after it.The term can also refer to an interval of time begi