'signpost' originates from Middle English, specifically the words 'sign' and 'post', where 'sign' meant 'a mark or indication' and 'post' referred to 'a pole or stake'.

'sign' and 'post' were combined in Middle English to form 'signpost', which has retained its meaning into modern English.

Initially, it meant 'a post with a sign', and this meaning has largely remained the same in modern usage.