There’s a beautiful scene in the memoir-turned-musical Fun Home where an elementary school–aged Alison Bechdel spots a masculine deliverywoman in a diner, an encounter that sparks a kind of epiphany about her own identity. The little girl admires the woman from across the room, grasping for the right words to describe her fascination. “I thought it was supposed to be wrong / But you seem OK with being strong,” she sings. “It’s probably conceited to say / But I think we’re alike in a certain way.”

Young Bechdel marvels at the woman’s short haircut, butch swagger, and “lace-up boots.” The focal point of her ode, the unmistakable signifier that gives the song its title, is the “ring of keys” on her belt.

That song, and the scene in the 2006 memoir from which the musical was adapted, was based on a true-life moment Bechdel experienced in the 1960s. But look to the waistbands of any modern-day gaggle of queer women, and you’re liable to find a critical mass of jingling metal attached.

The beltside key ring is one of the most enduring sartorial symbols of lesbian culture, one of the few stereotypes of our kind that’s both inoffensive and true. Baby gays searching the internet for ways to find their people and send out lesbian vibes will learn that “the universal key chain signal for lesbians is the carabiner clip” and even straight people know it. When Pharrell Williams wore a sparkly yellow carabiner on his pants at the 2015 BET Awards, comedian Fortune Feimster joked that he’d picked up a lesbian’s keys. Kate McKinnon’s clichéd lesbian character in 2015’s Sisters has a whole collection of carabiners to her name.

“As a kid, I thought bunches of keys on belts were just really cool, but I don’t think I ever saw a woman wearing one,” Bechdel told me in an email. “Then after college, I moved to New York City and got one myself. … I can’t quite remember what possessed me. Maybe I saw someone else doing it. Or maybe I just saw it at the hardware store and thought, ‘what the hell! I’m in New York, I can do whatever I want.’ ” When I first came out, the key ring was the first visual cue I learned of my new world, picked up through anthropological surveys of lesbian dance parties. Many years and worn-out carabiners and photos of friends’ key-adorned hips later, I still wear my keys on my belt for fashion and function.

Both fashion and function are integral to the origin story of the key ring as lesbian flagging device. The style stems from the history of butch women being attracted to the masculine aesthetic of blue-collar jobs, and being shunted into such jobs because they didn’t fit the gender molds of the other career tracks—stewardess, waitress, secretary—available to women in generations past. (Lesbians were also more likely to have jobs in general in previous eras, as they didn’t have male spouses to breadwin and demand kept homes.) Without strict dress codes, women who worked as custodians, postal workers, and mechanics could stretch the boundaries of accepted gender presentations. They also needed easily accessible keys.

“[Key rings are] a phallic symbol—they’re all about potency, agency, capability,” Bechdel said. In the ’70s, the prevailing flavor of lesbian feminism was anti-butch, painting masculine women as man-imitators and butch-femme relationships as retrograde. By the time Bechdel got to New York in the ’80s, she said, that conventional wisdom had shifted “so that a timid college-educated white lesbian like myself could walk around feeling tough and transgressive with a leather key ring on her belt loop.”

Another root of the lesbian key-ring tradition connects to kink culture and gay cruising. People involved in the leather scene used to (and sometimes still do) wear their keys clipped to their belt loops based on their sexual preferences: on the right side to indicate that the wearer is a bottom, and left if she’s a top. One oft-repeated theory says a Village Voice writer once jokingly suggested that gay men should dispense with this binary key system and develop a more complex system to reflect a broader taxonomy of sexual desire, thus sparking the creation of the hanky code.

The semiotics of the carabiner have largely been divorced from sex for today’s lesbian, but key clips are still reliable identity flagging implements. Bechdel calls her key ring “an identifier, a way to make myself visible to other lesbians—and not even in a sexual way, just as a way of connecting and finding community.” Krista Burton, who used to write the fantastic queer blog Effing Dykes, once surmised that carabiners kept their place on the lesbian belt loop through the years because of their functionality and simplicity, qualities many of our favored fashions share. Lesbians are way less likely than straight women to carry purses around, but women’s jeans don’t allow much pocket room for a bundle of keys. A ring of keys presents an elegant solution.

A key ring also makes a perfect visual signifier for a culture that contains a full spectrum of gender presentations. Short nails are one well-known way to spot a lesbian in the wild, but not everyone has sex the same way, and apparently there’s some high-femme workaround with cotton balls and latex gloves? Carabiners, which range from the utilitarian to the adorned, know no gender. Side-shaves and other alternative lifestyle haircuts have been usurped by straight women, muddling one of our clearest indicators; with their fancy purses and dresses, straight women are unlikely to ever adopt the belt loop key ring en masse.

This is one reason why “Ring of Keys” has held such profound resonance for lesbians and queers of all genders: Moments of identification and affinity are essential for communities facing discrimination, assimilation, and erasure. Masculine-of-center lesbians in particular have long served as a cultural punch line, what Fun Home lyricist Lisa Kron has called “a stock character of ridicule.”* “Ring of Keys” is a powerful repudiation of that archetype, an earnest appreciation of the butch aesthetic viewed through an object that’s helped lesbians find one another for generations.

But now that the sacred symbol has been broadcast from Broadway stages and across national airwaves, it feels a bit conspicuous for the artist responsible. “Nowadays I keep my keys on a carabiner, and stow them in my bag,” Bechdel told me. “There are certain occasions when clipping them onto my belt loop makes the most sense, but ever since ‘Ring of Keys’ became the national butch anthem, I feel strangely self-conscious about doing that.”

Read more from Outward’s Lesbian Issue.

*Correction, Dec. 21, 2016: This piece originally misspelled Lisa Kron’s last name.