why do people call christmas xmas

Christmas is often shortened to Xmas because the word Christmas contains the Greek word "Christ," which starts with the letter X. The letter X is also used as a symbol for Christ in certain contexts, such as in the X-shaped symbol known as the "Chi Rho," which is often used as a symbol for Christ. Therefore, by shortening the word "Christmas" to "Xmas," people can still symbolically reference the importance of Christ while also using fewer letters.