(CNN) — If you've ever crammed into the back of a Toyota with one or more males over the age of seven, you're likely familiar with the phenomenon recently popularized as manspreading.

A target of women's websites and public transit authorities, the practice involves the widening of a man's legs while seated such that those adjacent must bonsai themselves into what little sittable space remains in a bus or airplane row. Or, in the case of subway benches, often abstain from sitting at all.

Who are these entitled thigh wideners? And why has this only now become a recognized social phenomenon?

What critical man-mass elevated this interpersonal mansgression to the level of cultural manstay? And -- at the risk of mansplaining -- it turns out there's much in a name, albeit an unimaginative one.

Because, while the formation of the seated V is as old as recumbency itself, calling it manspreading has helped it achieve such widespread manfamy.

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Fixing the prefix

There was a time when a man could do or wear something without it necessitating its own gender-specific prefix -- slip on a pair of flip-flops, grab your rucksack and hit the town with one of your bros.

Now, however, those are mandals on your feet, a manbag on your shoulder and a man date to which you've just committed yourself for the evening.

It's a means of (lazily) ascribing male characteristics to characteristically female things -- some would say to the detriment of both genders, but with the express intent of ridiculing the former.

There's no question: It's getting tougher and tougher to be a man in this world.

Admittedly, we're nowhere near that trend actually ascending to the level of qualifiedly "tough" at all, but the Oxford English Dictionary isn't helping matters.

Last year, the gold mandard (sorry) of English elocution dignified with its own entry the word "manspreading," defined as "the practice whereby a man, especially one traveling on public transportation, adopts a sitting position with his legs wide apart, in such a way as to encroach on an adjacent seat or seats."

Cheap but effective, the term has only recently gained traction, but the practice predates the OED itself. In 1836, The Times of London published a series of guidelines for considerate coexistence on public transportation titled the Omnibus Law.

Manspread mic drop

Right there at No. 5 (out of 12) are the underpinnings of what we would come to know 180 years later as manspreading: "Sit with your limbs straight, and do not with your legs describe an angle of 45, thereby occupying the room of two persons."

It was evidently one of the earliest recorded mic drops, because nearly two centuries would pass before the next major polemic on the subject, an AM New York article published in 2014, would again admonish public transportation's most self-indulgent seat imperialists.

It, however, is regarded as the first such screed to give name to their crimes against plier-legged fellow passengers.

"Manspreading" had gone mainstream.

What was once an unspoken infraction was now a full-blown cultural construct. And if you ask Oxford, New York's Metropolitan Transportation Authority is to credit/blame.

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New name, old problem

By Oxford English Dictionary standards, the term "manspreading" skyrocketed into common use, powered by the MTA's fall 2014 Courtesy Counts campaign.

Now the agency has launched an exhibit dedicated in part to the social misdemeanor, called "Transit Etiquette Or: How I Learned to Stop Spitting and Step Aside in 25 Languages."

The exhibit is out to illustrate that while the term might be modern, the act of manspreading is as old as group seating.

"There have been campaigns like this going back to almost the beginning of the subway," says Senior Manager of Exhibitions for the MTA's New York Transit Museum Rob Delbagno, suggesting a measure of futility in trying to repel the manspreading menace.

"We found stuff going back to 1915, and most of the problems they were talking about then were the same as now," he concedes.

Posters and other various signage from the collection depict subway-riding vulgarians in the 1940s littering, blocking doors, resting their feet on seats and, of course, describing leg angles greater than 44 degrees.

In a country where obesity rates are an escalating epidemic and a town where space is a dwindling premium, manspreading takes on a defense readiness condition beyond mere novelty. But it isn't limited to the Five Boroughs.

"As we started looking at it, we realized this is not unique to New York, so we started looking around and pulling together things from all over the world," Delbagno says.

Part public service, part cultural chronicle, the exhibit has been extended to October 30 due to overwhelming popular response, providing ample time for the MTA to educate mass transit's masses on this mandemic.

Which kind of monster does manspreading make you?

But when you really need to judge someone, there's no substitute for science, which is already hard at work to classify perpetrators of lap-tuse seating.

"It needs more academic attention and I think it's going to get it now," UCLA professor of behavioral psychology Uri Maoz says regarding manspreaders.

Unfortunately for those seeking closure, there might actually be an evolutionary explanation motivating these femoral fascists.

"There is some research that suggests that under some circumstances women might find this more attractive," Maoz says.

Indeed, preliminary findings reported in the Proceedings of the National Academy of Sciences suggest that adopting an "expansive (vs. contractive) body posture increases one's romantic desirability" at a rate 25% greater than when not being a terrible person.

In other words, chicks dig manspreading whether they know it consciously or not.

"Postural expansion can dramatically increase a person's chances of making a successful initial romantic connection," the report concluded, because it's "considered to express both dominance and openness."

Changing habits

Of course, the possible traits associated with manspreading aren't all so winsome.

"My intuition would be that people who say it's fine would probably also have other characteristics, like a more positive attitude toward porn, for instance," Maoz says.

Preferred subway reading material notwithstanding, if evolutionary manspreading and the messages crafted to combat it have existed for centuries, what hope should riders of public transportation have that any of these efforts will do something to stop these narcissistic knee Nazis?

The MTA's Delbagno urges patience -- and reminds us to be grateful manspreading doesn't come with any emissions.