The Collaborative International Dictionary of English v.0.48:

four-in-hand \four-in-hand\ n.
   1. A long necktie that is tied in a slipknot with one end
      hanging in front of the other.
      [WordNet 1.5]

   2. a coach pulled by four horses with one driver.

   Syn: coach, coach-and-four.
        [WordNet 1.5]

The Collaborative International Dictionary of English v.0.48:

Four-in-hand \Four"-in-hand\, a.
   Consisting of four horses controlled by one person; as, a
   four-in-hand team; drawn by four horses driven by one person;
   as, a four-in-hand coach. -- n. A team of four horses driven
   by one person; also, a vehicle drawn by such a team.
   [1913 Webster]

         As quaint a four-in-hand
         As you shall see.                        --Tennyson.
   [1913 Webster]

WordNet (r) 3.0 (2006):

four-in-hand
    n 1: a long necktie that is tied in a slipknot with one end
         hanging in front of the other
    2: a carriage pulled by four horses with one driver [syn:
       coach, four-in-hand, coach-and-four]