The Collaborative International Dictionary of English v.0.48:
Monogyny \Mo*nog"y*ny\, n. [See Monogynia.] 1. Marriage with the one woman only. [1913 Webster] 2. (Bot.) The state or condition of being monogynous. [1913 Webster]WordNet (r) 3.0 (2006):
monogyny n 1: having only one wife at a time