what is bc
B.C. is an abbreviation for âBefore Christ.â A.D. is an abbreviation for âanno Domini,â which is Latin for âin the year of our Lord.â B.C. and A.D. are commonly used to count years in time.Jesus Christâs birth is used as a starting point to count years that existed before (B.C.) and after (A.D.) He was born.For example, the year 532 B.C. refers to the time 532 years before A.D. 1, when Christ was assumed to have been born.esus Christâs birth is used as a starting point to count years that existed before (B.C.) and after (A.D.) He was born. For example, the year 532 B.C. refers to the time 532 years before A.D. 1, when Christ was assumed to have been born.