'knob' originates from Middle English, specifically the word 'knobbe', ultimately from Old Norse 'knappr', where 'knappr' meant 'lump' or 'protuberance'.

'knob' changed from the Middle English word 'knobbe', which came from Old Norse 'knappr', and eventually became the modern English word 'knob'.

Initially, it meant 'a small lump or protuberance', but over time it evolved to include meanings such as 'a rounded handle', 'a control on equipment', and several informal or slang senses.