a. The joint between the thigh and the lower leg, formed by the articulation of the femur and the tibia and covered anteriorly by the patella.
b. The region of the leg that encloses and supports this joint.
2. An analogous joint or part of a leg of a quadruped vertebrate.
3. The joint between the femur and the tibia in an insect leg.
4. Something resembling the human knee, such as a bent piece of pipe.
5. The part of a garment, as of trousers, that covers the knee.
6. A vertical, often conical, woody projection arising from the roots of certain swamp-growing trees: cypress knees.
tr.v. kneed, knee·ing, kneesIdiom:
To strike with the knee.
take a knee
1. To kneel down on one knee.
2. Football To kneel down on one knee while holding the ball so as to down the ball, as in one's own end zone for a touchback.
[Middle English, from Old English cnēo; see genu-1 in the Appendix of Indo-European roots.]
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2018 by Houghton Mifflin Harcourt Publishing Company. 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.