Eccentricity
WordNet
noun
(1) Strange and unconventional behavior
(2) A circularity that has a different center or deviates from a circular path
(3) (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"
WiktionaryText
Etymology
From Greek εκκεντρικός ekkentrikos, from εκ- ek "from" + κεντρικός kentrikos "of the center, central"
Noun
- The quality of being eccentric; any eccentric behaviour.
- The ratio, constant for any particular conic section, of the distance of a point from the focus to its distance from the directrix