Joseph Fielding Smith makes semantic distinction between "polygamy" and celestial marriage.
Joseph Fielding Smith, Blood Atonement and the Origin of Plural Marriage (Salt Lake City: Deseret News, 1905), 48
In using the term "polygamy" in reference to the principle that was taught and practiced by the Saints, I desire it distinctly understood that I use it in the sense of a man having more than one wife. Polygamy, in the sense of plurality of husbands and of wives never was practiced in the Church of Jesus Christ of Latter-day Saints in Utah or elsewhere; but Celestial marriage — including a plurality of wives — was introduced by the Prophet Joseph Smith and was practiced more generally by the saints under the administration of President Brigham Young.