A conveyance for letters or dis-patches. The word is derived from “positi,” the horses carrying the letters or dispatches being kept or placed at fixed stations. The word is also applied to the person who conveys the letters to the houses where he takes up and lays down hls charge, and to the stages or distances between house and house. Hence the phrases, post-boy, post-horse, post-house, etc. wharton
Source: Black’s Law Dictionary 2nd Ed (1910)
