This worksheet defines the terms "BC" (before Christ) and "AD" (anno Domini) and briefly explains how they are used. "CE" (common era) and BCE (before common era) are also explained. I use this worksheet with my sixth grade class when we start to learn about world history.
Anno Domini--(AD or A.D.) and before Christ (BC or B.C.) are used to label or number years in the Julian and Gregorian calendars. The term anno Domini is Medieval Latin, which means in the year of the Lord but is often translated as in the year of our Lord. It is occasionally set out more fully as anno Domini nostri Iesu (or Jesu) Christi ("in the year of Our Lord Jesus Christ").