“Vaccine” was already a common-enough word in English. But the jaunty “vax” — a word that has skulked around the margins of the language since it first appeared in the 1980s — surged dramatically, occurring 72 times more frequently in September 2021 than a year earlier.

“All these other vaccine words increased, but nothing like vax,” said Fiona McPherson, senior editor for new words at Oxford Languages, which publishes the Oxford English Dictionary. “It’s a short, punchy, attention-grabbing word.”

“And speaking as a lexicographer, it’s also quite a productive one,” she continued. “You see it used in all sorts of combinations to make new words.”