n. pl. ec·cen·tric·i·ties
a. The quality of being eccentric.
b. Deviation from the normal, expected, or established.
2. An example or instance of eccentric behavior.
3. Physics The distance between the center of an eccentric and its axis.
a. The ratio of the distance of any point on a conic section from a focus to its distance from the corresponding directrix. This ratio is constant for any particular conic section.
b. Such a ratio used to define the shape of the orbit or path of a celestial body or satellite.
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2022 by HarperCollins Publishers. All rights reserved.
Indo-European & Semitic Roots Appendices
Thousands of entries in the dictionary include etymologies that trace their origins back to reconstructed proto-languages. You can obtain more information about these forms in our online appendices:
The Indo-European appendix covers nearly half of the Indo-European roots that have left their mark on English words. A more complete treatment of Indo-European roots and the English words derived from them is available in our Dictionary of Indo-European Roots.