means The joints in the middle of your legs that bend, connecting thigh to shin and letting you walk, kneel, and crouch.

from From Old English 'cneow,' a word with deep Germanic roots and likely a far cousin to Latin 'genu' and Greek 'gony' — all tracing back to the same ancient Proto-Indo-European root for 'knee.' The silent 'k' we still spell but no longer say is a fossil of a time when English speakers actually pronounced that opening consonant, before centuries of lazy mouths quietly dropped it.