2 definitions
for mail boat
From The Collaborative International Dictionary of English v.0.48 :
mailboat \mail"boat`\, mail boat \mail" boat`\n.
1. a boat that carries the mail.
Syn: mail boat, packet, packet boat.
[WordNet 1.5]
From WordNet (r) 2.0 :
mail boat
n : a boat for carrying mail [syn: mailboat, packet, packet
boat]