Workplace discrimination against employees who are single; the negative stereotyping of single people. Also: single-ism.
The growing numbers of individuals marrying later or not marrying at all, combined with high divorce rates, have resulted in a growing number of adults who will live a considerable portion of their adult lives as singles. Despite this trend, recent empirical investigations suggest that singles face a particular form of stigma and discrimination, termed "Singlism".
—"The stigma of "Singlism": ever-single women's perceptions of their social environment," SAGE Insight, June 22, 2011
Singledom and a massive case of "singlism" are red hot right now as Samantha Jones cracks menopause jokes at 54 as she romps in the desert with her three fab friends in Sex and the City 2.
—Leanne Italie, "Single and happy: believe it or not," The Associated Press, June 10, 2010
Anne, a Toronto interior designer, agrees that being married can be helpful in the workplace. "I have more to talk about with clients. . ." she says, adding: "It shows a maturity. And when you're developing business, you need things to relate to. Marriage and kids...."
Bella DePaulo, a visiting professor of psychology at the University of California, Santa Barbara, who is writing a book tentatively titled Singled Out, calls such pro-marriage discrimination "singlism."
—Tralee Pearce, "One is not the loneliest number," The Globe and mail, July 3, 2004
Here a much earlier citation that doesn't quite fit my definition, but covers what could be called social discrimination against singles:
[B]ut it doesn't take long for a widowed or divorced parent to find that our couple-oriented society has forged a modern phenomenon which might be termed "singlism." singlism wasn't invented, it just exists. Invitations are made for pairs—dinner parties, tennis games, dances or theatre-going are done in duos.
—"The Single Parent Volume 18," Parents Without Partners, January 1, 1975