Easton's Bible Dictionary: M. G. Easton, M.A., D.D.
Lord of the opening, a god of the Moabites (Num. 25:3, 31:16; Josh. 22:17), worshipped by obscene rites. So called from Mount Peor, where this worship was celebrated, the Baal of Peor. The Israelites fell into the worship of this idol (Num. 25:3, 5, 18; Dt. 4:3; Ps. 106:28; Hos. 9:10).