eccentricity

noun

ec·​cen·​tric·​i·​ty ˌek-(ˌ)sen-ˈtri-sə-tē 

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

Synonyms

• characteristic
• trick
• trait
• idiosyncrasy
• mannerism
• quirk
• singularity
• peculiarity
• individualism
• curiosity
• oddity
• habit
• twist
• tic

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

Cena, despite his attempts at wackadoo eccentricity, seldom has enough energy to create meaningful contrast with Elba’s straight man (in fact, Elba is often the funnier and sharper of the two), and most dialogue scenes end up flat and repetitive. —Siddhant Adlakha, IndieWire, 27 June 2025

That’s a straightforward but wonderfully satisfying template, and the kind of thing that’s become a rarity in a genre where the main character’s eccentricities might as well be a shorthand that distinguishes one show from another. —Nina Metz, Chicago Tribune, 11 June 2025

Nani is the only one who understands Lilo’s eccentricity, but Nani is overstretched and struggles to care for her little sister, resulting in the state threatening to take Lilo away from Nani. —Dani Di Placido, Forbes.com, 28 May 2025

The party is now divorced from his eccentricities, which, though appealing to some of the most radical voters, alienate the rest. —Alejandro Antonio Chafuen, Forbes.com, 13 June 2025

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

Rhymes for eccentricity

• authenticity
• chromaticity
• concentricity
• domesticity
• elasticity
• electricity
• iconicity
• metallicity
• multiplicity
• specificity
• synchronicity
• analyticity

Kids Definition

eccentricity

noun

ec·​cen·​tric·​i·​ty ˌek-ˌsen-ˈtris-ət-ē 

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