That made me remember back to my first years teaching. I was in a rural, mostly Southern Baptist, community. I was teaching the Middle Ages, and with that came a lesson on the history of the Christianity (not theology, mainly the many splits in the faith). The history of the Middle Ages is closely tied up with Catholicism. One of my students, a rather bright one at that, proclaimed that she thought we were learning about Christianity, and that these catholic people aren't Christian.
I knew better than to argue. She explained that the Southern Baptist faith started the day Jesus was born. With that amount of intentional ignorance and refusal to entertain historical fact I had to way of teaching her the truth. (The 70 of the unit test did open up a bit of dialogue, though).
So I looked it up:
1. of, pertaining to, or derived from Jesus Christ or His teachings: a Christian faith.
2. of, pertaining to, believing in, or belonging to thereligion based on the teachings of Jesus Christ: Spain is a Christian country.
3. of or pertaining to Christians: many Christian deaths in theCrusades.
4. exhibiting a spirit proper to a follower of Jesus Christ; Christlike: She displayed true Christian charity.
5. decent; respectable: They gave him a good Christian burial.
7. a person who believes in Jesus Christ; adherent of Christianity.
8. a person who exemplifies in his or her life the teachings of Christ: He died like a true Christian
And since everything I've read about Mormonism (as crazy as it can be sometimes) involves them following numbers 7 and 8 of the above definition.... I conclude that Mormons are Christian. (along with this definition)
The Church of Jesus Christ of Latter-day Saints (the LDS Church or, colloquially, the Mormon Church) is the largest denomination in the Latter Day Saint movement, a Christian primitivist* movement started by Joseph Smith during the American Second Great Awakening.
*Christian primitivism, also called restorationism, is the belief that a purer form of Christianity should be restored using the early church as a model