n. One who rides over a postroad to carry the mails.
the GNU version of the Collaborative International Dictionary of English
n. One who rides over a post road to carry the mails.
The Century Dictionary and Cyclopedia
n. One who rides post; a mounted mail-carrier.
Word Usage
"All right, Mr. Clarke, I've got to have a postrider to carry a very important message to Dover, Delaware, to get a man back here from Dover by nine o'clock tomorrow morning."