Once, a generation was called “us.” Or “them.” Maybe “the grownups.” Or “kids these days” — if, indeed, anyone ever gave a passing thought to lumping together people with nothing more in common than an age span.

Then in January of 1970, a story in the Washington Post used the term “baby boomer” to describe Americans born between 1946 and 1964, a period that long had been called the “baby boom” spawned by the postwar prosperity.

The moniker caught fire, and cultural shorthand would never be the same.

Consider the images that come to mind for the term “millennial” (twentysomethings struggling to land jobs in their degree fields) or “Generation X” (parents living in their SUVs while trundling between their kids’ activities) or “Greatest Generation” (anyone in a retirement home).

The brushstrokes may be broad, but such terms both define and target each generation. Little wonder, then, that naming rights for the upcoming group already are being claimed.

The buzz is driven in part by a new book by Paul Taylor with the Pew Research Center, that insatiable collector of public opinion. In “The Next America: Boomers, Millennials, and the Looming Generational Showdown,” Taylor argues that shifts in demographics, economics, culture and technology are reshaping how generations regard each other.

In a recent appearance on Jon Stewart’s “The Daily Show,” Taylor was asked what he’d call the upcoming generation. He said he didn’t yet know.

Responded Stewart: “You just opened up a contest, my friend.”

Everyone under one umbrella

People have been anticipating this conversation for some time, said Mary Meehan, a Minneapolis trend-seer who co-founded Panoramix Global, which does consumer research.

Naming a generation helps define it, she said, which makes it easier for marketers to pitch to its members.

“This is not to pigeonhole people, but to help define who we are as a nation,” Meehan said. “Then marketing and consumer research will begin to delve deep into who a specific audience is and what motivates them.”

She added: “It’s a shorthand.”

Baby boomers got named partly because there were just so many of them, but also because they were born as television was becoming popular.

“There were all these kids and you saw television programs like ‘Howdy Doody’ directed at children, who were this new market,” Meehan said. Parents, whom Tom Brokaw would later dub the “Greatest Generation” (Meehan calls them “the matures”), were trying to provide all they could for their children, she added, making the “boom” resound even more loudly.

Given that boomers cast themselves as movers and shakers unlike any who had moved or shaken before, members of Generation X — born between 1964 and 1980 — struggled to forge a clear identity.

Nor was anyone really trying to name them, either, Meehan said, adding that X actually is a symbol for the unknown.

Then in 1991, Douglas Coupland wrote a book called, “Generation X: Tales for an Accelerated Culture, ” and the term Gen X caught on.

About the same time, historians Douglas Strauss and Neil Howe came up with “13th Generation” for what they tracked as the 13th generation since Ben Franklin’s time — in other words, when the United States became an independent country.

Erudite, yes, but society already was starting to pick up the pace and favored a brisk Gen X to all those syllables. Still, the duo recovered by coining “millennials” for those born between 1981 and 2000, which bested Ad Age’s more derivative Gen Y.

Enter iGens?

The next generation still is being born, so its name can’t yet be determined. According to a Pew Research Center blog post: “Their critical formative moment or moments may not yet have happened. It’s really too early to tell exactly which of the many forces acting upon them will be the most broadly applicable and impactful.”

Susan Brower, the state demographer for Minnesota, agrees, noting that definitions get set in motion “when there is a new or defining event, or cultural tie that comes out of social commentary.”

Pop cultural names don’t add much value to the work of demographers, who are more concerned with marking a generation’s start points and end points, she said.

It’s a determination done in retrospect, and is less a “clean” parade of dates than you might think, given events of history, Brower added. “There’s very little precision around where one generation begins and another ends,” she said. “But it’s still important for us to think about the generations’ demographics because they behave differently.”

She wouldn’t hazard a guess about the next term: “We’ve yet to see.”

Others, however, are eager to speculate.

When historians Strauss and Howe sponsored a website contest in 2005, not long after the Sept. 11 attacks, the clear winner was Homeland Generation.

In 2012, the marketing firm Frank N. Magid Associates came up with the term “plurals.” Plurals, it contends, will be the United States’ last generation with a Caucasian majority, will exist in far more diverse social circles than previous generations, and also is “the most positive about America becoming more ethnically diverse.”

Among the names being perused at Pew are the TwoKays or 2K’s (born after 2000), Generation i (or iGeners and iGens), @generation, the Swipe Generation, the Tweennials, Screeners and Evernets.

Clearly, it’s possible to overthink this.

Mary Meehan’s Panoramix Global favors Gen We, partly to poke a gentle stick at Generation Me — a term that, interestingly, has been used to describe both baby boomers and millennials as being insufferably self-absorbed (which suggests that various generations often delight in poking sharp sticks at each other).

Meehan believes that members of Gen We will be constantly connected and rarely alone technologically (although perhaps physically), given the reach of social media.

Right now, it’s impossible to know what name eventually will stick, she said.

“There tends to be tipping point of sorts when a term begins to be used enough to be recognized.”

Evernets? iGens? Stay tuned.