Definition of: eccentric

(ek·sen′·trik) adjective
1. Departing from the usual custom or practice; peculiar; erratic.
2. Not in the center.
3. Math. Not having the same center: said of circles, ellipses, spheres, etc.: opposed to concentric.
4. Not being a perfect circle, as an ellipse.
5. Of or pertaining to an eccentric.
6. Not holding to an identical purpose.
7. Removed or apart from a nerve center.
8. Colloq. Odd or unconventional to a degree short of mental unbalance: said of persons whose actions are considered peculiar to a marked degree. See synonyms under IRREGULAR, ODD, QUEER.
—noun
1. Mech. A disk mounted out of center on a driving shaft, bound to it by a key, and surrounded by a collar or strap connected with a rod, effecting a crank motion.
2. One who or that which is eccentric.
3. Math. A circle not having the same center as another that partly coincides with it: also spelled excentric. [<LL eccentricus <Gk. ekkentros <ek- out, away + kentron center]
—ec·cen′tri·cal adjective
—ec·cen′tri·cal·ly adverb
ECCENTRIC
r. Driving shaft, eccentric to center of disk d. k. Key binding disk to shaft. c. Collar connecting with rod r.