A courier, or runner, was an individual who served as a messenger for various important deliveries.
In starship classification, a courier was a type of vessel functioned in a similar capacity, often as a specialized transport rendezvousing with other ships in deep space or at space stations.
Klaang was a courier for the Klingon High Command in 2151 when his scoutship crashed on Earth. (ENT: "Broken Bow")
Morn was given the task of being the courier that delivered a message to Starfleet that the Dominion was about to bring down the minefield blocking the Bajoran wormhole. (DS9: "Favor the Bold")
In the 32nd century, the Mercantile, an Orion-operated marketplace located at Requiem, Hima, employed couriers for picking up and delivering items. Payment was in the form of dilithium. On their left sleeves, the couriers wore a piece of technology which was used as identification. In the 3180s, Cleveland Booker, Cosmo Traitt, and Zareh worked as couriers. (DIS: "That Hope Is You, Part 1", "Far From Home")
Long range shuttles were used as couriers during the 23rd century. (Star Trek: The Motion Picture)
The USS Hera was on a routine courier mission when it disappeared in 2370. (TNG: "Interface")
The Maquis utilized modified support couriers in their attacks on the Cardassians in the DMZ. (DS9: "The Maquis, Part I")
In 2371 Rom requested that a special relief shipment he ordered on behalf of Zek be sent by high warp courier. (DS9: "Prophet Motive")
Types of couriers