The Collaborative International Dictionary of English v.0.48:

Convoy \Con*voy"\, v. t. [imp. & p. p. Convoyed; p. pr. & vb.
   n. Convoying.] [F. convoyer, OF. conveier, convoier. See
   Convey.]
   To accompany for protection, either by sea or land; to attend
   for protection; to escort; as, a frigate convoys a
   merchantman.
   [1913 Webster]

         I know ye skillful to convoy
         The total freight of hope and joy.       --Emerson.
   [1913 Webster]