Noun

plural marriage

1. A form of polygamy formerly practiced by Mormons.

Polygamy (called plural marriage or the Principle within Mormonism) was a defining characteristic of early Mormonism, and continues to be the defining characteristic of Mormon fundamentalism. The practice of polygamy was instituted in the 1830s by founder Joseph Smith, Jr., and was a contributing factor leading to his 1844 assassination. It was also a factor in the 1857 invasion of Utah by the United States Army, and was the cause of an intense legal conflict during the late 1800s, culminating in the temporary legal dissolution of The Church of Jesus Christ of Latter-day Saints (LDS Church) and its institutions. The LDS Church officially abandoned the practice in 1890. That year the president of the United States declared polygamy illegal. Since 1890, members of the LDS Church who are found practicing or promoting polygamy are excommunicated.

Today, the practice of plural marriage continues among tens of thousands of Mormon fundamentalists, mostly in the western United States, Canada, and Mexico, where it is generally illegal. However, practitioners are almost never prosecuted unless there is evidence of abuse, statutory rape, welfare fraud, or tax evasion. Mormon fundamentalists believe that plural marriage where a man has more than one wife is a requirement for obtaining the highest "degree" within the highest of three Mormon heavens.