BC stands for "Before Christ." It is used to denote years before the estimated birth of Jesus Christ, with the years counting backward from 1 BC, which is the year immediately before AD 1 (the year traditionally considered the birth year of Jesus)

. This dating system was devised in the 6th century by the monk Dionysius Exiguus and has been widely used in the Gregorian calendar, which is the global standard calendar today

. The abbreviation BC is always placed after the year number (e.g., 44 BC), indicating the number of years before Christ's birth

. In summary:

• BC = Before Christ
• Used to label years before the birth of Jesus Christ
• Years count backward from 1 BC, which precedes AD 1
• Commonly used in historical and religious contexts worldwide