Mormonism is a term used to describe the religious, ideological, and cultural elements of certain branches of the Latter Day Saint movement, specifically, The Church of Jesus Christ of Latter-day Saints (LDS Church) and Mormon fundamentalism.
The term derives from the term Mormon, which was originally used as a pejorative term to describe those who believe in the Book of Mormon, a sacred text that has been added to the religion's canon in addition to the Bible (Old and New Testaments). Today, Mormonism is no longer offensive when used in reference to the Utah-based LDS Church, including cultural Mormons, and several smaller denominations and sects of Mormon fundamentalism whose adherents embrace the term despite opposition by the LDS Church. However, The Church of Jesus Christ of Latter-day Saints and its members rarely describe their beliefs as Mormonism. Most other Latter Day Saint movement denominations oppose use of the term in reference to their faith, and such usage is now rare and may be considered offensive.