High street (Old English heahstræte) was the word before 17c. applied to highways and main roads, whether in the country or town, especially one of the Roman roads. In more recent usage, it generally is the proper name of the street of a town which is built upon a highway and was the principal street of the place.
Highway robbery, robbery committed near a highway, is from 1707, formerly the only sort punishable in common law by death; as a trivial expression for something too costly, by 1886.
updated on September 05, 2021