Bc Ad Calendar. Simply put, bce (before common era) is a secular version of bc (before christ). Bc means before christ, and ad means anno domini (medievil latin for in the year of our lord).
Difference between ad and bc anno domini, which is regularly abbreviated ad, or found in the form of anno domine, is a designation that is used to label the years in an era on the. Simply put, bce (before common era) is a secular version of bc (before christ).