Definition of knee noun from the Oxford Advanced American Dictionary

knee

noun

/ni/

the joint between the top and bottom parts of the leg where it bends in the middlea knee injuryI grazed my knee when I fell.He went down on one knee and asked her to marry him.She was on her knees scrubbing the kitchen floor.Everyone was down on (their) hands and knees (= crawl on the floor) looking for the ring.My knees were knocking (= I was frightened).2 the part of a piece of clothing that covers the kneeThese jeans are torn at the knee.a knee patch3 the top surface of the upper part of the legs when you are sitting down synonym lapCome and sit on Daddy's knee.IDIOMS

at your mother's knee

when you were very young

I learned these songs at my mother's knee.at your mother's knee

bring someone to their knees

to defeat someone, especially in a war

bring to their knees

bring something to its knees

to badly affect an organization, etc. so that it can no longer function

The strikes brought the industry to its knees.bring to its knees

on bended knee(s)

if you ask for something on bended knee(s), you ask for it in a very anxious and/or humble way

I'd go down on bended knee if I thought she'd change her mind.on bended kneeon bended knees

put someone over your knee

to punish someone by making them lie on top of your knee and hitting their buttocks

put over your knee

weak at/in the knees

(informal) hardly able to stand because of emotion, fear, illness, etc.His sudden smile made her go weak in the knees.weak at the kneesweak in the knees