say it: ek-suhn-TRIS-uh-tee
eccentricity is a noun meaning "strange and unconventional behavior". It carries 3 recorded senses.
strange and unconventional behavior
(geometry) a ratio describing the shape of a conic section; the ratio of the distance between the foci to the length of the major axis
“a circle is an ellipse with zero eccentricity”
geometry
a circularity that has a different center or deviates from a circular path
Forms marked · are formed by the regular rule rather than recorded in the source data. English keeps a few hundred irregulars and the rest follow the pattern, so the rule is right far more often than not — but it is a rule, and the mark says so.
Definitions, synonyms and semantic relations for eccentricity come from Princeton University’s WordNet. The pronunciation comes from the CMU Pronouncing Dictionary. Commonness is measured against a corpus of everyday English. Full sources and licences.