Definition of "nonmonogamy"

Though nonmonogamy seems to be on the rise — or at least society is more open about it than ever before — families consisting of three or more parents can face challenges that are in some ways different from, and similar to, those faced by divorced parents, single parents and L.G.B.T.Q. parents.

2020 August 4, Cynthia McKelvey, “The Challenges of Polyamorous Parenting”, in The New York Times‎