Definition of the word knuckle

The word "knuckle" derives from the Middle English word "knekel," which in turn comes from the Old English word "cynegganlēac." The Old English word can be traced back to the Proto-Germanic "knākeliz," meaning "joint." Initially, the Old English word "cynegganlēac" referred to any joint in the body, but by the Middle English period, it specifically referred to the joints in the fingers. This change may have been influenced by the Old Norse word "kni" which meant both "knee" and "finger joint." The spelling of the word changed over time, with "knekel" being pronounced "knokel" in Middle English. The word's pronunciation evolved further into its modern-day form of "knuckle." Today, the term "knuckle" is commonly used to describe the rounded, bony prominences at the top of the fingers and the base of the thumb. It has also been used in slang to refer to the head or face in a derogatory way, but this usage is less common.