Happy Xmas

An informal shortening of the phrase "Happy Christmas." The use of X in place of "Christ" comes from the Greek letter chi, the first letter in the Greek spelling of Christ, Χριστός (Christós). Primarily heard in UK, Ireland. Their card reads, "Happy Xmas, from the Nichols Family." Aw, isn't that nice? A: "What's that song you're humming?" B: "Oh, the one by John Lennon—'Happy Xmas,' I think it's called?" C: "'Happy Xmas (War Is Over)'." Unfortunately, I can't fit much on this sign—will "Happy Xmas" do?