👓 adventitious

Merriam-Webster’s Word of the Day for October 4, 2026 is:

adventitious • \ad-ven-TISH-us\  • adjective

Adventitious is a formal word that most often describes something that comes from an outside source, and is neither inherent or innate. In botanical contexts especially, the word also describes something that arises or occurs sporadically, or not in the usual or expected location.

// The house is like a museum—beautifully restored, full of period pieces, and with no adventitious elements in view.

// The bumps growing along the stem of the tomato plants are adventitious roots.

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Examples:

“Although individual [creosote bush] plants have a lifespan of 30-90 years, adventitious shoots grow up from roots. These develop into new plants, clones of the original, that form a ring around the spot where the original plant stood.” — Joshua Siskin, The Orange County (California) Register, 5 July 2025

Did you know?

Early in Charlotte Brontë’s novel Jane Eyre, the titular Jane ascertains that her new employer, Mr. Rochester, whom she thinks is decidedly not handsome, has “other qualities, intrinsic or adventitious” that “atone for the lack of mere personal attractiveness.” We all possess intrinsic and adventitious qualities—the former, we’re born with, and the latter we gain through life’s lessons. English speakers anglicized the Latin word adventīcius in the early 17th century to apply it with its Latin meaning: “coming from outside; external, foreign.” The word still carries this meaning primarily, but by the close of the 17th century it was also being used, especially in botany, to describe that which arises or occurs sporadically or in other than the usual location, as when adventitious roots appear where roots generally are not found.