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 of eccentricity

• 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

Where the movie’s true eccentricity comes in is in its combination of breezy comedy with shocking brutality and gore, perhaps most exemplified in an oddly casual moment in a morgue where Seagal and Wayans find a clue in the form of a serial number on a dead woman’s breast implant. —Jim Hemphill, IndieWire, 5 June 2026

Luna spends the day in the socially conscious sign of Aquarius, shifting the emotional tone toward intellect, perspective, eccentricity and detachment. —Valerie Mesa, PEOPLE, 5 June 2026

Sure, there are several social butterflies across the zodiac—Leo, Sagittarius, Aquarius, to name a few—but Geminis are famous for their magnetic eccentricity which captivates just about anyone in their orbit. —Kara Jillian Brown, InStyle, 21 May 2026

Of course, in addition to being perfect by becoming a doctor, John had selected, despite her eccentricities, the perfect mate in their parents’ eyes. —Literary Hub, 8 May 2026

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