'unknot' originates from Old English elements: the prefix 'un-' and the word 'cnotta' (knot), where 'un-' meant 'reverse/remove' (or 'not' in some uses) and 'cnotta' meant 'knot'.

'unknot' developed through Middle English forms such as 'unknoten' or 'unknoten' and eventually became the modern English verb 'unknot' (and the gerund/participle 'unknotting').

Initially it meant 'to loosen or undo a knot', and this basic meaning has largely remained the same into modern usage.