knuckle

The word 'knuckle' has a distinctly Germanic lineage, tracing back to Middle English 'knokel' and further to Middle Low German 'knökel', meaning a small bone or knuckle. These terms are diminutive forms, suggesting a "little bone" or "prominence," likely derived from a Proto-Germanic root related to the concept of a bone or a hard lump. The semantic journey is straightforward, moving from a general term for a small bone or joint to its specific modern application to the finger joints. The word's form has remained remarkably stable in English, retaining its core sense of a bodily articulation while also extending metaphorically to mechanical parts, such as in a hinge.

This is a simplex word of Germanic origin. The modern form 'knuckle' evolved from the Middle English 'knokel', which is a diminutive form of a word related to a bone or joint. Its functional role is as a complete lexical root.