If you're single and dating and aren't 25 anymore, here's a quandary you've no doubt encountered: how to describe the object of your affection.

Does "boyfriend" or "girlfriend" seem silly? "Significant other" too stilted? "Partner" not quite right?

"People feel a real need for a term that refers to one's romantic partner that does not sound childish," says Jesse Sheidlower, editor at large of the Oxford English Dictionary. " 'Partner' sounds too official. 'Companion' sounds too unromantic. 'Lover' is too explicit. 'Boyfriend' and 'girlfriend' seem inappropriate unless you're a teenager. 'POSSLQ' sounds too stupid or bureaucratic." (POSSLQ, an acronym for "Persons of Opposite Sex Sharing Living Quarters," was used in the late 1970s by the U.S. Census.)

The need for just the right descriptor is a signal of the societal changes surrounding social identities, says linguistics professor Arnold Zwicky, a visiting professor at Stanford University.

According to the most recent Census data, 42 percent of U.S. residents — about 92 million Americans ages 18 and older — are unmarried. More than 30 million live alone, making up 27 percent of all households.

The number of unmarried opposite-sex couples who live together has also increased to 5 million cohabiting households.

"People are living longer," Zwicky says. "People are divorcing more. One member of a couple is alone after a spouse dies. People who might not have been on the sexual marketplace years ago now find themselves in it or choosing not to go into it. Now, it's an issue for a lot of people."

Lynn Bartholome knows this issue firsthand. The associate professor of English and philosophy at Monroe Community College in Rochester, N.Y., is chairwoman of the Popular Culture Association and the American Culture Association, international academic groups that study everyday culture worldwide.

She's also 57 and dating.

"I've talked about this with some of my female friends," Bartholome says. "I don't know what to say. I say, 'the guy I'm dating.' I really honestly feel weird calling him my 'boyfriend.' Is a man you date and are intimate with a 'beau,' 'a significant other,' a 'partner'? I don't know."

A 2005 study of 115 people ages 21 to 35 who were either cohabiting or had lived with a romantic partner notes that the lack of proper terms often leads to awkward situations, such as someone upset over not being introduced in social situations to avoid the question.

"Our findings suggest that cohabiters frequently refer to their partners as girlfriend/boyfriend or fiance, although there appears to be no universally accepted term or language. At times, the lack of a term can create conflict and problems," the study says. It was written by Wendy Manning of Bowling Green State University and Pamela Smock of the University of Michigan and was published in the Journal of Marriage and Family.

The aging of baby boomers may be one reason society has been seeking a mature version of "boyfriend" and "girlfriend," says Dennis Baron, an English and linguistics professor at University of Illinois at Urbana-Champaign.

Grant Barrett, a lexicographer and dictionary editor who co-hosts the public radio show "A Way With Words," says such questions are asked fairly regularly on the show.

"If you're in your 50s and living with somebody in a romantic relationship, what to call each other? You can say 'boyfriend' and 'girlfriend,' but you're not 13 and it doesn't really fit. You can say 'significant other,' but there's no love in that. One caller suggested 'paramour,' but that's old-fashioned," he says. "There are a ton of different options, and none of them seems to work."

Barrett recalls his grandmother facing the same questions. Her romantic relationship lasted into her 80s.

"She did call him 'boyfriend,' knowing full well how ridiculous it sounded."