means The joint connecting the thigh and lower leg, allowing the leg to bend.

from From Old English 'cneow,' tracing back to the Proto-Germanic 'knewam' and ultimately a Proto-Indo-European root '*genu-' meaning the bend in a leg. That same ancient root branches out to the Latin 'genu' and Greek 'gony' — which is why your knees and your genuflection share a deep family resemblance. The silent 'k' we now stumble past was once fully voiced; English speakers used to actually pronounce it, until the sound quietly slid off the front of the word, leaving the letter behind like a forgotten name tag.