packet boat

Short definition from Wiktionary

Noun

1. 1
   An ocean-going ship chartered by the government to carry the mail and official communications.
2. 2
   A boat that carried mail, cargo, and, in later years, some passengers along a regularly scheduled route up and down a river or canal.
3. 3
   A boat specifically designed to provide transportation to passengers on a regular schedule up and down a river or canal.
4. 4
   Alternative form of packet boat: Government-commissioned mail ship.
5. 5
   Alternative form of packet boat: River or canal boat that carries mail.
6. 6
   Alternative form of packet boat: Passenger boat.