What is the meaning of Kneecap?

The flat, roundish bone in the knee.

A metal cover trim that fits over a panel rib after it has been cut and bent.

A cap or strong covering for the knees, used chiefly for horses, to protect their knees in case of a fall.

To destroy the knees of (a person), usually by shooting at the knees, as a punishment carried out by criminals or terrorists.

To attack (someone) in a way that is excessively and needlessly damaging: To cut (someone) off at the knees.

Source: wiktionary.org