'derail' originates from French, specifically the word 'dérailler,' where 'dé-' meant 'off' and 'rail' referred to 'rail.'

'dérailler' transformed into the English word 'derail' in the 19th century.

Initially, it meant 'to go off the rails,' but over time it evolved to include the broader sense of 'obstructing or diverting a course.'