The patriarchal priesthood (or Abrahamic priesthood) is associated with the patriarchal order found in Mormonism and is especially connected with celestial marriage.
In the largest Latter Day Saint denomination, The Church of Jesus Christ of Latter-day Saints (LDS Church), the patriarchal priesthood is sometimes confused as one of the types or "orders" of priesthood, however, there are only two orders: the Aaronic priesthood and the Melchizedek priesthood; the patriarchal priesthood should also not be confused with the calling of the patriarch. Boyd K. Packer, an LDS Church apostle, has explained that the patriarchal priesthood is included in the Melchizedek priesthood:
There are references to a patriarchal priesthood. The patriarchal order is not a third, separate priesthood. (See D&C 84:6–17; D&C 107:40–57.) Whatever relates to the patriarchal order is embraced in the Melchizedek Priesthood. "All other authorities or offices in the church are appendages to [the Melchizedek] priesthood." (D&C 107:5.) The patriarchal order is a part of the Melchizedek Priesthood which enables endowed and worthy men to preside over their posterity in time and eternity.
— Packer, Boyd K. (February 1993), Ensign, "What Every Elder Should Know—and Every Sister as Well: A Primer on Principles of Priesthood Government"