BC stands for "Before Christ," referring to the years before the estimated birth of Jesus Christ. It counts backward from 1 BC (the year before Jesus's birth) and is placed after the year number (e.g., 44 BC)
. AD stands for the Latin phrase "Anno Domini," which means "in the year of our Lord." It denotes the years after the birth of Jesus Christ, starting with AD 1 and continuing to the present. AD is placed before the year number in English usage (e.g., AD 70)
. Together, BC and AD form a dating system centered on the birth of Jesus Christ as the dividing point in history. This system was introduced in the 6th century and is used in the Gregorian calendar, the most widely used calendar today
. There are also secular alternatives: BCE ("Before Common Era") corresponds to BC, and CE ("Common Era") corresponds to AD. These terms are used to avoid religious connotations but refer to the same time periods
. In summary:
- BC = Before Christ (years before Jesus's birth, after the year number)
- AD = Anno Domini ("in the year of our Lord," years after Jesus's birth, before the year number)
This system marks the traditional Christian timeline division, with AD starting at year 1, not year 0
