Definition from Wiktionary, the free dictionary
1634, from Christianity, replacing Christ with the abbreviation Xt (from Ancient Greek Χ (Kh, the letter chi), the first letter of Χριστός (Khristós, “Christ”) + t, the last letter of "Christ"). Compare the more common Xmas.
- Alternative form of Xianity (“abbreviation of Christianity”).
1950 December 14, C. S. Lewis, Letter to Sheldon Vanauken:
- I believe Buddhism to be a simplification of Hinduism and Islam to be a simplification of Xtianity.
See also: Xianity#Usage notes