'mail boat' definitions:

Definition of 'mail boat'

(from WordNet)
noun
A boat for carrying mail [syn: mailboat, mail boat, packet, packet boat]

Definition of 'mail boat'

From: GCIDE
  • mailboat \mail"boat`\, mail boat \mail" boat`\n.
  • 1. a boat that carries the mail.
  • Syn: mail boat, packet, packet boat. [WordNet 1.5]