A neologism is a newly invented word or phrase, or an existing word used in a brand new way. The word comes from Greek roots meaning “new word.”

Every word you know was once a neologism. “Telephone” was a neologism in the 1870s when Alexander Graham Bell needed a name for his invention. More recently, words like “podcast,” “blog,” and “emoji” were all neologisms that filled gaps in our vocabulary as new technologies emerged.

Sometimes neologisms catch on and become part of everyday language. Other times they fade away because people don't find them useful or because they sound too awkward. When J.K. Rowling wrote the Harry Potter books, she created neologisms like “Muggle” and “Quidditch” that millions of readers now recognize. Shakespeare was famous for coining neologisms, too.

You create a neologism when you combine words in new ways or invent terms for things that didn't have names before. If you and your friends make up a word for that feeling when you almost remember something but can't quite grasp it, you've created your own neologism. Whether it spreads beyond your friend group depends on whether others find it useful enough to adopt it.