Kneebone

Part of speech: noun

Definitions

1. The small flat bone that covers and protects the front of the knee joint in humans and many animals
2. A rounded bone positioned at the front of the knee, sitting over the joint where the thigh meets the shin
3. The sesamoid bone that sits in front of the knee joint and helps the leg extend more efficiently

Etymology: Kneebone is a plain compound of "knee" and "bone," and its history is simple. Both parts are native English: "cnēo" (knee) and "bān" (bone) are recorded in Old English, so the word is inherited rather than borrowed. The compound itself, meaning the kneecap, is a straightforward English formation, and the sense has stayed essentially the same since it was first used. The "front knee bone" sense is the one most dictionaries give, and it refers specifically to the patella, the flat bone that sits in front of the knee joint. Older English speakers sometimes used the word more loosely, and it appears in medical and anatomical contexts as well as everyday speech. Because the parts are so old and transparent, the word needed no special coinage or borrowing to arise.

Synonyms: kneecap, patella