'unbraid' originates from the prefix 'un-' meaning 'not' or 'reverse' and the word 'braid', which comes from Old English 'bregdan', meaning 'to weave or twist'.

'bregdan' transformed into the Middle English word 'breiden', and eventually became the modern English word 'braid'. The prefix 'un-' was added to form 'unbraid'.

Initially, 'bregdan' meant 'to weave or twist', but with the prefix 'un-', it evolved to mean 'to undo a braid'.