Meaning of B.C., A.D. and Christmas

What does B.C. stand for in Latin?  Such as A.D. stands for "anno domini."
   B.C. is short for "Before Christ" or "Before The Common Era." (B.C.E.)
   Since there is no agreement on when time began, Europeans adopted the convention of recording dates in terms of whether they occurred before or after the birth of Jesus Christ, by assigning the YEAR ONE to the year of Jesus' birth. (Muslims do the same thing, only they use a different year for their YEAR ONE, the year of
Mohammed's return to Mecca.) Nowadays, historians believe that Europeans of the Middle Age got the date of Jesus' birth wrong, but nevertheless, we continue to
use the system they devised.
  Assuming that our starting point is the YEAR ONE (there is no YEAR ZERO), then BC , meaning "before Christ" is the abbreviation used for years that occured
before the YEAR ONE. AD means "anno Domini" (Latin for "year of our Lord") and is used on all dates that come after YEAR ONE.