'knows' originates from Old English, specifically the word 'cnāwan', which comes from Proto-Germanic and ultimately from the Proto-Indo-European root '*ǵneh₃' meaning 'to know'.

'knows' (as a form of 'know') changed from Old English 'cnāwan', passed through Middle English forms such as 'knowen' or 'knowe', and eventually became the modern English verb 'know' with its inflected forms like 'knows'.

Initially it meant 'to get to know, recognize, perceive', and over time it evolved to the current general sense of 'to have knowledge of or be aware of'.