National Thesaurus Day is a holiday that’s observed every year on January 18th and honors the man who compiled Roget’s Thesaurus, Peter Mark Roget. He was a British physician, lexicographer, and the founding secretary of The Portico Library. In 1852, he published the Thesaurus of English Words and Phrases. This is why the holiday celebrates the date of his birth in 1779. Anyone who considers themselves a word fanatic might want to try celebrating this holiday when it comes around.

The History of National Thesaurus Day

Although we don’t know who started this holiday, we do know that the day was established to commemorate the birthday of Peter Mark Roget. He was born on January 18, 1779, in Soho, London, and studied medicine at the University of Edinburgh, graduating in 1798. He retired from professional life in 1840 and published the Thesaurus of English Words and Phrases in 1852. Roget died on September 12, 1869, at the age of 90 in West Malvern, England.

Fun Thesaurus & Word Facts

Since we’re talking about this holiday, we thought we would dig up some interesting facts about the thesaurus and words in the English language. So let’s not waste any more time and jump right into the following fast facts.

• Thesaurus comes from the Greek word “thesauros,” a word that means “treasure.”
• The plural of thesaurus is “thesauri” or “thesauruses.”
• Early French thesauruses were actually dictionaries.
• Peter Mark Roget wrote the first modern thesaurus.
• The infinity sign, a sideways “8,” is known as a Lemniscate.
• The longest word found in a modern dictionary is 45 letters long.
• One single piece of confetti is known as a “confetto.”
• Clint Eastwood is an anagram of the phrase “Old West Action.”
• Walrus comes from the Old English word “horschwael,” which translates to “horse whale.”
• Penguin comes from the combination of two Welsh words: “Pen,” which means “head,” and “Gwyn,” which means “white.”
• “Nudiustertian” is a word that means the day before yesterday.
• The opposite of déjà vu is “jamais vu,” a feeling that something familiar feels foreign.
• John Milton invented the word “Pandemonium” for the capital of hell in his epic poem “Paradise Lost.”
• “Apron” used to be spelled “Napron” in the 14th century. Eventually, it lost its “n.”
• A “qualtagh” is the first person you see after you leave your home.
• “Alligator” came from the Spanish words “el lagarto,” which means “The Lizard.”
• “Goodbye” comes from the 16th-century word “Godbwye,” which was shorthand for “God Be With Ye.”
• In 2011, the words “FYI,” “LOL,” and “OMG” were added to the dictionary.
• In 2021, the words “Cancel Culture,” “Long-Hauler,” and “Gig Worker” were officially added to the dictionary.

Observing National Thesaurus Day

Breaking out your thesaurus (if you have one) or checking out an online thesaurus to learn a new word are both excellent ways to spend this holiday. It’s also a good day for playing word games with your friends and family members. While you’re observing this holiday, don’t forget to use the hashtag #NationalThesaurusDay to let everyone know about this holiday.