eccentricity

noun

ec·​cen·​tric·​i·​ty ˌek-(ˌ)sen-ˈtri-sə-tē How to pronounce eccentricity (audio)
plural eccentricities
1
a
: the quality or state of being eccentric
b
: deviation from an established pattern or norm
especially : odd or whimsical behavior
2
a
: a mathematical constant that for a given conic section is the ratio of the distances from any point of the conic section to a focus and the corresponding directrix
b
: the eccentricity of an astronomical orbit used as a measure of its deviation from circularity

Examples of eccentricity in a Sentence

Some people weren't very tolerant of his eccentricity. Talking to her plants is one of her many eccentricities.
Recent Examples on the Web
Examples are automatically compiled from online sources to show current usage. Read More Opinions expressed in the examples do not represent those of Merriam-Webster or its editors. Send us feedback.
Set on more than five acres, the 5,000-square-foot main residence exudes that traditional Hamptons style, but also features design touches that reflect the eccentricity of Palm Beach and the charm of the European countryside. Tori Latham, Robb Report, 17 July 2025 An engineer at the University of Arizona's Catalina Sky Survey, David Rankin, said recent estimates of the object's eccentricity are about 6. ArsTechnica, 2 July 2025 The home’s eccentricities are in keeping with Schachter’s own. Wendy Goodman, Curbed, 6 May 2025 The eccentricity refers to how noncircular an orbit is. Darryl Z. Seligman, The Conversation, 3 July 2025 See All Example Sentences for eccentricity

Word History

Etymology

borrowed from Medieval Latin excentricitāt-, excentricitās, from ecentricus, excentricus "not having the earth exactly at its center, eccentric entry 1" + Latin -itāt-, -itās -ity

First Known Use

1545, in the meaning defined at sense 1a

Time Traveler
The first known use of eccentricity was in 1545

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Cite this Entry

“Eccentricity.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/eccentricity. Accessed 28 Aug. 2025.

Kids Definition

eccentricity

noun
ec·​cen·​tric·​i·​ty ˌek-ˌsen-ˈtris-ət-ē How to pronounce eccentricity (audio)
plural eccentricities
1
a
: the quality or state of being eccentric
b
: something that does not follow an established pattern, norm, or rule
especially : unusual behavior
2
: the amount by which a nearly circular path is not circular
an orbit's eccentricity

More from Merriam-Webster on eccentricity

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