"Xmas" and "X-mas" are common abbreviations of the word "Christmas". They are sometimes pronounced "eksmas", but they, and variants such as "Xtemass", originated as handwriting abbreviations for the pronunciation "Christmas". The "-mas" part came from the Latin-derived Old English word for "mass".

This abbreviation is widely used but not universally accepted. Many do not know about its antiquity and believe it to be of commercial origin and thus demeaning to Christ, whilst others find it a helpful abbreviation.