Xmas, come of age

Christmas, Childermas

Xmas
WRITTEN ABBREVIATION FOR Christmas:
Happy Xmas to all our customers.

(from Cambridge Advanced Learner's Dictionary)
According to the Oxford English Dictionary, the use of "Xmas" as an abbreviation for "Christmas" goes back to around 1500. And it may go back even many years before that.

"X" is the symbol for the Greek letter "chi,"讀如"開" which is the first letter in the Greek word Christos, meaning "Christ." Indeed, some scholars will tell you the use of "chi" or "X" as an initial for Christ goes all the way back to some Christian texts from the first century.


come of age
1 to reach the age when you are legally recognized as an adult and become old enough to vote

2 If something has come of age, it has reached its full successful development.

Over dinner Santiago Saavedra, a publisher who came of age during Franco’s later decades, winced when the subject of the new law surfaced. He saw it as an attack on his generation. “We are made to feel guilty for having led our lives,” he said.