Rommy Hunt Revson was renting a house in Southampton, N.Y., in 1986, stressed from her recent divorce from a Revlon heir, John Revson, when she conceived of a hair band to hold a ponytail without damaging the hair.

“I don’t know why, but I became somewhat determined to figure out an invention that used fabric instead of plastic for the hair,” Ms. Revson told Talk Business & Politics, a news website in Arkansas, where she lived briefly, in 2016.

“My friends tried to get me to put that down and go with them to the beach as summer was about to end,” she added, “but something told me to keep working on this hair accessory.”

She bought a used sewing machine, taught herself to sew and combined fabric and elastic (like those in her pajamas) into a prototype of what she called a scunci (pronounced SKOON-chee), naming it after her poodle. Within a year she got a design patent, which protected how it looked but not how it was made, and found a licensee.

The scunci soon became better known as the Scrunchy, the ubiquitous, inexpensive hair accessory of the late 1980s and ’90s that was worn by millions of women, including stars like Madonna, Janet Jackson, Demi Moore, Sarah Jessica Parker and the Olsen twins in the sitcom “Full House.” In an episode of “Seinfeld,” Kramer muses that a woman he is sweet on should replace her tortoise hair clip with a velvet Scrunchy.

“Rommy was a smart woman who managed to take a hair accessory item that in any other person’s hands would have been a flea market item,” Lewis Hendler, a top executive and lawyer at New L&N Marketing and Sales, Ms. Revson’s licensee from 1989 until the license expired in 2001, said in a phone interview. “Her woman’s fashion sense saw the potential in it going from a utilitarian hair holder to a fashion item.”

Ms. Revson died on Sept. 7 in a hotel room near the Mayo Clinic in Rochester, Minn., where she was being treated for Cushing’s disease and Ehlers-Danlos syndrome, which affects the body’s connective tissue, like the skin, joints and blood vessel walls, said her cousin Charles Brower. Her estate lawyer, Alan Rothfeld, said the cause of death was a ruptured ascending aorta. She lived in Wellington, Fla., near West Palm Beach.

Rommy Kolb was born on Feb. 15, 1944, in White Plains, N.Y., to William and Rose Kolb. Her father was a painting contractor, her mother a homemaker.

Ms. Revson worked in Lord & Taylor and other stores in Manhattan in the 1960s. In the 1970s and early ’80s, she was a singer, songwriter and voice teacher. She adopted the surname Hunt and sang at Manhattan clubs like Ibis, Reno Sweeney and s.n.a.f.u.

When she made her debut at Reno Sweeney in 1979, the critic John S. Wilson of The New York Times wrote, “As a singer, she has range, control and a fine sense of shading. And as a performer, she projects strongly and on a variety of levels.”

The gossip columnist Earl Wilson noted in 1982 that Ms. Revson “had returned to sing at Ibis after three years and was good to our eyes (and ears).”

But she disliked the nighttime lifestyle and eventually left singing, Mr. Brower said. With the scunci she found a new direction — though she was not, it seems, the first to develop something like her patented creation. By some accounts, a man named Philips Meyers came up with a similar one in 1963, but it did not catch on.

Once Ms. Revson’s product reached the market, it proved to be very popular, but her licensee at the time could not manage the quick surge of orders and went out of business. Copycat manufacturers flooded the market with what came to be called Scrunchies.

“I thought I would be a bag lady 10 years from now saying, ‘Hey, I invented those,’” Ms. Revson told The Washington Post in 1995.

But retailers like Walmart, Kmart, Target, CVS and Walgreens, which had been making bootleg scuncis, agreed to become licensees and abide by the patent, Mr. Hendler said. His company paid Ms. Revson $1 million annually over a dozen years, he said.

But she was not satisfied; she wanted the damages that New L&N had passed up in reaching the agreement with the copycats. She sued the company (which eventually changed its name to Scunci International) and received about $1 million, Mr. Hendler said. She lost a lawsuit against her lawyers over legal fees, however, and had to pay them $732,370.

Judd Burstein, the lawyer who represented her in the latter case, said in a phone interview, “She was a talented but unyielding person who had a good heart.”

Ms. Revson is survived by a son, Nathaniel Hunt. Her four marriages ended in divorce.

The fame of the scunci — or Scrunchy — has outlasted Ms. Revson’s patent.

Colonel Pamela Melroy wore a blue one on her space shuttle missions in 2000 and 2002 to keep her hair from floating free and getting entangled in equipment. She donated it to the National Air and Space Museum in Washington in 2004.

In her 2014 memoir, “Hard Choices,” Hillary Clinton wrote that an alternative title suggested for the book was “The Scrunchie Chronicles: 112 Countries and It’s Still All About My Hair.”

And in an article in The Wall Street Journal in 2018 about a Scrunchy revival, Justice Ruth Bader Ginsburg of the Supreme Court said that her collection of them “is not as large as my collar and glove collection, but scrunchies are catching up.”