Merriam-Webster's Word of the Day for December 5, 2025 is: inoculate • \ih-NAHK-yuh-layt\ • verb To inoculate a person or animal is to introduce immunologically active material (such as an antibody or antigen ) into them especially in order to treat or prevent a disease. Inoculate can also mean "to introduce (something, such as a microorganism) into a suitable situation for growth," and in figurative use, it can mean "to protect as if by inoculation" or "to introduce something into the mind of." // In 1796, the English physician Edward Jenner discovered that inoculating people with cowpox could provide immunity against smallpox. // The cheese is inoculated with a starter culture to promote fermentation. See the entry > Examples: "Truffle farmers ... inoculate oak or hazelnut seedlings with truffle spores, plant the seedlings and wait patiently often a decade or more for the underground relationship to mature. The eventual harvest is a reward for years of cooperation between tree and fungus." — David Shubin, The Weekly Calistogan (Calistoga, California), 30 Oct. 2025 Did you know? If you think you see a connection between inoculate and ocular ("of or relating to the eye"), you have a good eye—both words look back to oculus , the Latin word for "eye." But what does the eye have to do with inoculation? Our answer lies in the original use of inoculate in Middle English: "to insert a bud into a plant for propagation." The Latin oculus was sometimes applied to things that were seen to resemble eyes, and one such thing was the bud of a plant. Inoculate was later applied to other forms of engrafting or implanting, including the introduction of vaccines as a preventative against disease.
