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

• crotchet
• curiosity
• erraticism
• idiosyncrasy
• individualism
• kink
• mannerism
• oddity
• peculiarity
• quiddity
• quip
• quirk
• singularity
• tic
• trick
• twist

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

Lives Lived: John Peck, known as the Mad Peck, was a cultural omnivore whose work as an underground cartoonist, artist, critic and disc jockey had a dry humor and an ornate eccentricity. —German Lopez, New York Times, 8 Apr. 2025

In a stroke of luck, however, the two features have aligned to create a satisfying image that is helping scientists understand the eccentricities of star formation. —Jack Knudson, Discover Magazine, 25 Mar. 2025

Meet the quirky, lovable Sycamore family, who embrace life on their own terms with boundless enthusiasm and eccentricity. —Encinitas Advocate, San Diego Union-Tribune, 19 Mar. 2025

Anderson often encourages eccentricity in his stars, but Life Aquatic inspired a warmer, more vulnerable side in Blanchett, who plays the woman who attracts both famed oceanographer Steve Zissou (Bill Murray) and the sweet, dopey Ned Plimpton (Owen Wilson), who may be Steve’s son. —Tim Grierson, Vulture, 15 Mar. 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