NEW YORK — The slang term at the center of a political brouhaha swirling around former FBI Director James Comey is an old one, likely originating as food-service-industry jargon before extending to other contexts. Some of that spread has given rise to accusations from Republicans that it was meant as a threat to President Donald Trump.

In a since-deleted Instagram post, Comey wrote “cool shell formation on my beach walk” to accompany a photo of shells displayed in the shapes of “86 47.”

He said in a follow-up post that he took it only as a political message since Trump is the 47th president, and to “86” something can be to get rid of it, like a rowdy patron at a bar or something that is no longer wanted.

But Trump and other Republicans took it more ominously. They say Comey, with whom Trump has had a contentious relationship, was advocating violence against the president, given that the slang term has at times been used as a way to mean someone’s killing.

The Secret Service interviewed Comey on Friday. Any decision on whether charges should be filed would be up to Attorney General Pam Bondi, Trump said, though there’s a high bar in proving that comments or posts amount to direct threats of violence.

Homeland Security Secretary Kristi Noem confirmed in a post on X that Comey had been interviewed and said she would “take all measures necessary to ensure the protection” of Trump.

The Secret Service is part of the Department of Homeland Security. An interview is a standard part of an investigation into comments perceived as potentially threatening but does not suggest that charges are being considered.

FBI Director Kash Patel said the bureau was also supporting the investigation.

The slang origins of “86” go back to codes used in diners and restaurants as staff shorthand in the 1930s or so, said Jesse Sheidlower, adjunct assistant professor in Columbia University’s writing program and formerly editor-at-large for the Oxford English Dictionary.

It meant that something on the menu was no longer available. Over time, he said, related uses developed.

“The original sense is, we are out of an item. But there are a bunch of obvious metaphorical extensions for this,” he said. “86 is something that’s not there, something that shouldn’t be there like an undesirable customer. Then it’s a verb, meaning to throw someone out. These are fairly obvious and clear semantic development from the idea of being out of something.”

He said there have been uses of it as a euphemism for killing someone, as in certain fiction stories, but that usage is not nearly as widespread. More likely it means to jettison something that is no longer useful — a definition parodied in the popular 1960s TV show “Get Smart,” whose lead character was known — wink, nudge — as Agent 86.

That type of meaning is reflected in the entry for “86” from Merriam- Webster, the dictionary used by The Associated Press.

That definition says the meaning is “to throw out,” “to get rid of” or “to refuse service to.” While referencing that there have been uses of it to mean killing, the dictionary said, “We do not enter this sense, due to its relative recency and sparseness of use.”

But Trump and his administration insist that was the intent of the usage in Comey’s initial post Thursday.

“He knew exactly what that meant,” Trump said during a Fox News interview Friday. “A child knows what that meant. If you’re the FBI director and you don’t know what that meant, that meant assassination. And it says it loud and clear.”

Comey said on social media: “I posted earlier a picture of some shells I saw today on a beach walk, which I assumed were a political message. I didn’t realize some folks associate those numbers with violence.”

Trump fired Comey as FBI director in 2017, early in Trump’s first term. In 2018, in a book, Comey said Trump was unethical and “untethered to truth.”

That a slang reference can cause this kind of anxiety is not surprising, especially at a time like the one we are living in, said Nicole Holliday, acting associate professor of linguistics at the University of California, Berkeley.

“I think that because we are in a hyperpartisan, polarized culture, everything is a Rorschach test,” she said. “We’re very sensitive about any indication that people are part of our in-group or part of the out-group.”