'knot' originates from Old English 'cnotta', from Proto-Germanic '*knuttą', where the root 'knu-' meant 'to tie or bind'.

'knot' changed from Old English 'cnotta' to Middle English 'knotte' and eventually became the modern English word 'knot'. The nautical use (speed) developed later from knots tied on a log-line used to measure a ship's speed.

Initially it referred to a lump or protuberance and a tied lump; over time it broadened to include specific uses such as a fastening made by looping rope and the later technical meaning of a unit of speed ('knot').