1. (n) The power or authority to act in God’s name. The priesthood is conferred to worthy men and young men. The Aaronic priesthood, or priesthood of Aaron, is the “preparatory” priesthood, usually conferred to a boy when he turns 12. The Melchizedek priesthood is the “higher” priesthood, usually conferred to a man when he turns 18 or 19 (right before becoming a Mormon missionary.)
2. (n) The body of men and young men to whom the priesthood authority [referring back to #1] has been conferred.