Why Christmas is also called 'Xmas' ?

Christmas is also referred to as 'Xmas'.  'X' as used in 'Xmas' is traced back to the Greek word  for 'Christ' - 'Χριστός'  ( 'Christos') as used in the Greek version of New Testament.  The  first letter  of the Greek word for 'Christ' - 'chi' - resembles the letter  'X' ( pronounced 'ki' and the 'i'  is pronounced like 'i' in 'Kite'). 

Christians conveniently started using the Greek letter that resembles 'X' instead of the 'Christ'.  Later  the actual English letter 'X'  began to replace  'Christ' in 'Christmas'.  The usage was so popular that the old Christian community had resorted to extensive campaign to bring back 'Christ' to 'Christmas'. 

The term is generally used in written English especially greeting cards and is considered as informal term for Christmas. Several linguistic experts advise against use of the term in formal writing. 

ExploreABC team wishes a Merry Christmas to all its readers.