Abi Balingit knows she’s an adult. She has a day job as an ad operations manager for a music company and a side job as a cookbook author. She pays the rent for her Brooklyn apartment every month and files her taxes every year. Also, she is 28 years old. But when she logs onto X, formerly known as Twitter, she becomes a girl or “girlie” — and so do the other women she talks to there.

The “Depop girlies,” users on the fashion resale app, are upselling the Sandy Liang collaboration with Baggu, she observes. She and “the girls” are having brunch, or tea or a pasta night. When Balingit posts, it’s “for the girls.”

Who are all these girls, and where did they come from? Balingit said she is often addressing Gen Z or millennial women, but not always. A “girl” could be “anyone who doesn’t fall into the gendered idea of the word,” she said, or even “anyone on the internet.”

Online, if your ears can pick up the frequency of the word “girl,” you just might be one. And as a girl, there is almost no behavior or activity you can’t claim as your own. Inspired by Megan Thee Stallion’s song “Hot Girl Summer,” you might go on a “hot girl walk” before seeing “Barbie,” a movie “for girls” — or “Oppenheimer,” also “for girls,” according to Balingit — and then put together a “girl dinner,” an assortment of snacks.

The word “girl” can be a noun, a verb, an adjective, or an exclamation, meaning something slightly different depending on how it’s said and who has said it — often it’s with the lilt of irony. It can begin a sentence, or punctuate one, or be a sentence on its own. In July, Vanity Fair writer Delia Cai proclaimed: “We’ve Reached Peak Girl.”

Yet despite the word’s flexibility, “girl” usually works to establish an in-group and relish a particular kind of bond.

“I think especially if you’re among strangers or something, if you get the ‘girl,’ it’s like you’re accepted in this circle,” said Ashley Reese, 32, a writer in Brooklyn who said she used “girl” more often than “woman” to talk about herself and her female friends. “There’s a communal element.”

This kind of term is known to rhetoric experts as a “vocative,” which is used to “call someone in,” said Nicole Holliday, an assistant professor in the department of linguistics and cognitive science at Pomona College. On the internet, where thousands of strangers may be reading one’s missives at any point, it can be useful to make it clear who should be listening.

A post on X that sought recommendations from “scent girlies,” for example, was really saying, “‘People who identify as not-male or as not-a-straight-male and have this interest, give me information,’” Holliday said. “It’s much easier to do it that way” — with “girlies” — “than it is to say what I just said.”

Like many popular colloquialisms, “girl” has a history in Black, transgender and gay communities, where the word may be used to acknowledge a shared experience or express a subtle form of solidarity that only those in the know would recognize.

“A lot of my experiences as an adult trans woman and as a writer have been reckoning with one’s girlhood when the world didn’t really let you have one, or didn’t admit that you had one,” said Casey Plett, 36, a founder of LittlePuss Press, a literary publisher. When she hears her friends say that the “girlies” are getting together — meaning a group of trans women — it’s “like a wink where we know what we’re talking about,” she said. “But I don’t think it’s uniquely trans.”

In her book “Girl Online,” Joanna Walsh argues that almost everyone becomes a girl when they log onto the internet, where users often share confessional writing and shuttle back and forth between “cute” and “smart.” They post memes and ironic observations one moment and level earnest critiques about politics or culture the next. What anyone really means when they post, whether they’re joking or serious, is often held coyly in suspension.

This mode is useful for being able to turn the tables on any argument quite quickly, Walsh said in an interview. “A lot can be learned from this slightly vaudeville tone,” she said.

Online and off, “girls” play on the stereotypes sometimes advanced in media and pop culture that portray them as vapid, self-absorbed and uncritical. For some, those labels can be all the more reason to embrace the word — not because it’s appealing to be diminished but because they present an opportunity to take advantage of those who might diminish you.

If someone can’t penetrate several layers of irony to determine whether you are merely pretending to be obtuse or are genuinely slow on the uptake, well, that’s a good laugh for the girls.

One might assume “girl” identity as a way to show naysayers just how clever girls actually are, or to show men how unserious those things to which they ascribe such importance may be. Claiming that something that is supposed to be “for boys” — say, baseball, the Grateful Dead, Karl Ove Knausgaard — is really “for girls,” is like a pinprick into a balloon, slowly letting the air out of masculinity.

“Femininity is still seen as silly and frivolous,” said Marlowe Granados, 31, who wrote in The Baffler in 2021 about what she argues is the sneaky subversiveness of the “bimbo,” whose humor is often at men’s expense, though they are none the wiser. “If people underestimate you, there’s actually more room to move around, and you can give people a shock when you prove them wrong.”

The use of the word “girl” or the performance of an exaggerated form of femininity, Granados said, may be “so subtle that people won’t get it or catch on.” But, she added: “You have the knowledge that you’re in on the joke, and that’s the whole thing.”

Balingit said that part of the approach was bringing levity to topics others might regard more earnestly. She cited a Substack newsletter called Boy Movies, by Allison Picurro. In the newsletter, Picurro has described Daniel Craig as “a girl actor trapped within the boy movie industrial complex.”

“You can take things for men and make them less serious,” Balingit added.

Perhaps that’s the kind of slippery power one might claim with a slippery word: With a simple gesture, any cultural artifact can be subsumed into what Balingit called “girl culture.” As self-described girls online assert ownership of Pilates and iced lattes as well as “Ulysses,” irritable bowel syndrome and tinned fish, so-called girl culture might just be the ruling order. And with actual teenage girls shaping much of pop culture and pioneering linguistic trends, some argue: Wasn’t it always that way?

The summer’s largest cultural events have been Taylor Swift’s Eras Tour, Beyoncé’s Renaissance Tour and the “Barbie” movie, which together swept social media and news headlines, and raked in a fortune in a swirl of friendship bracelets, sequined cowboy hats and Pepto-Bismol pink. (This is also to say that “girl” carries not only cultural capital, but also literal capital.)

“I think there’s always been these two parallel tracks,” said Samhita Mukhopadhyay, a former executive editor at Teen Vogue. “Girl culture is the dominant culture, but it has always been seen as less-than because it’s for girls.”

The word “girl” is in diametrical opposition not to “boy” but to “woman,” allowing women to enjoy simple feminine pleasures without the complications that some associate with womanhood. While women have adult responsibilities and are the subject of feminist discourse around contentious topics like gender pay gaps and unpaid domestic work, girls — at least as adult women conceive of them — are free to be lighthearted and fun-loving.

These girls are also perhaps a reaction to the so-called girl bosses who preceded them, high-functioning young women whose popular mandate was to hustle in the workplace in order to be taken as seriously as their male counterparts. While some sincerely embraced the label, others said it diminished ambitious women. And many more argued that would-be girl bosses seemed to use their power to uphold the same old patriarchal norms in the workplace. As that critique became more dominant, the girl boss’s stock began to fall.

Easier, then, to take “girl” and leave “boss” behind.

“I think there’s a safety in girlhood, in the mistakes and the naiveté, the youth and maybe even the beauty, which is all pushed by the media we consume,” Reese said. “Womanhood, meanwhile, is seeped with this lack of playfulness, seriousness, aging — the horror, right?”

An easy way to understand the gulf between the two words is to try swapping one with the other, said Hillary Keeney, 46, who lives in New Orleans and writes books on mysticism with her husband: “No one is going to say ‘woman dinner,’ or ‘women’s night out,’” she said. “That’s too serious.”

It is not the first time women have reached for a different word to encapsulate their ambivalent feelings about womanhood. Almost three decades ago, women wrestled with what at the time was a new embrace of “gal,” according to an article in The New York Times.

Restless once again, we are struggling to find a word that conveys snazziness and style, a casual term for the double-X set, a word without condescension or sneer, something more relaxed than ‘woman,’ something less fussy than ‘female,’ our equivalent of guy,” the Times journalist Natalie Angier wrote in 1995. “A delicious egalitarian word like … gal.”

Still, “gal” had its critics, just as “girl” does now. Upon catching wind of “girl dinner,” Joyce Meggett, 68, a librarian at Harry S. Truman College in Chicago, said she initially found the word condescending and dismissive. (Later, though, she realized that “the whole girl thing was a lot more nuanced than I thought.”)

And so while “girl” may fill a particular void at the moment — offering a capacious container for just about any feeling one might have about gender, adulthood, feminism and more — it probably won’t be long before it’s used a slightly different way or replaced altogether.

“I’ve always believed that gender is like language — it’s as infinitely broad and enormous as language is,” Plett said. “There’s an infinite amount of things you can do with language, to make new things and mold it to your own wishes.”

This article originally appeared in The New York Times.