Merriam-Webster's Word of the Day for December 14, 2025 is:

multitudinous • \mul-tuh-TOO-duh-nus\  • adjective

Multitudinous is a formal word with meanings that relate to multitudes. It can mean “existing in a great multitude”—that is, “very many”; or “including a multitude of individuals”; or “existing in or consisting of innumerable elements or aspects.”

// The two old friends reminisced about the multitudinous ways in which their lives had changed.

// The author’s appearance is expected to attract a multitudinous gathering that will fill the auditorium.

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Examples:

“Launched as Holton’s artistic inquiry into his own Chinese heritage, the project has evolved into a profound examination of family dynamics, migration, and cultural hybridity in contemporary New York, where the American identity is multitudinous.” — Natasha Gural, Forbes, 11 June 2025

Did you know?

“I am large, I contain multitudes.” So wrote Walt Whitman in his most celebrated poem, “Song of Myself.” He was expressing his ability to hold within himself contradictory statements, facets, opinions, beliefs, etc. Another, if less poetic, way of saying “I contain multitudes” might be “I am multitudinous,” using the sense of that five-syllable word meaning “existing in or consisting of innumerable elements or aspects.” Multitudinous doesn’t have a lot of meanings—three to be exact—but each one concerns, well, a lot. In addition to serving Whitmanesque purposes as noted above, multitudinous is the kind of highly expressive word that you can rely upon when you want something a little more emphatic than plain old numerous, as in “multitudinous possibilities.” Lastly, its original sense—still in use today—is a synonym of populous meaning “including a multitude of individuals,” as in “the multitudinous city.”