Some of the most frequently used words in the English language must have been created by someone with a devilish sense of humor. The word monosyllabic isn’t one syllable, long is only four letters, lisp is difficult to pronounce if you have a lisp, and synonym doesn’t have any synonyms. Or does it?
The answer to that last question is a bit complicated. Thesaurus.com lists metonym as a synonym of synonym, but their meanings aren’t exactly the same. The Oxford Dictionary of English Grammar defines synonym as “a word or phrase that means the same, or almost the same, as another in the same language.” Metonym, on the other hand, is defined as “a word or expression which is used as a substitute for another word or expression with which it is in a close semantic relationship.” For example, the crown can be used to refer to the king, and Washington sometimes refers to the U.S. government.
There is another possibility, though: poecilonym. This is probably the closest synonym of synonym, although it’s antiquated and rarely used. David Grambs, a lexicographer for American Heritage and Random House, included it in his 1997 book The Endangered English Dictionary: Bodacious Words Your Dictionary Forgot. The word is pronounced “PEE-si-lo-nim,” according to Grambs, who pays homage to its obscurity. “Maybe we could all use a few spanking old poecilonyms,” Grambs wrote. “Poecilonym? It’s an old synonym for synonym that you’ll find in these pages. But many words in this dictionary have no real counterparts in today’s English.”
Allen’s Synonyms and Antonyms from 1920 also listed poecilonym and another word—polyonym—as synonyms of synonym. However, it said both of these terms are rare. So technically, there are two other words that have the same meaning as synonym, but it’s a tough position to argue when those words are no longer in modern usage.
To add another dimension to this question, some have argued that there are no true synonyms at all, as every single word carries a different shade of meaning. “Even though the meanings of two words may be the same or nearly the same, they almost never are the same in connotation, distribution, and frequency,” Dictionary.com noted in 2018. “House and home may be offered as synonyms for each other, but we all know that they are not the same.”
So if you want to start using poecilonym or polyonym in place of synonym, you’d technically be correct—but don’t expect anyone else to know what you’re talking about.
A version of this story ran in 2018; it has been updated for 2023.
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