The Collaborative International Dictionary of English v.0.48:

Ditch \Ditch\, v. t. [imp. & p. p. Ditched; p. pr. & vb. n.
   Ditching.]
   1. To dig a ditch or ditches in; to drain by a ditch or
      ditches; as, to ditch moist land.
      [1913 Webster]

   2. To surround with a ditch. --Shak.
      [1913 Webster]

   3. To throw into a ditch; as, the engine was ditched and
      turned on its side.
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The Collaborative International Dictionary of English v.0.48:

Ditch \Ditch\, v. i.
   To dig a ditch or ditches. --Swift.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Ditch \Ditch\ (?; 224), n.; pl. Ditches. [OE. dich, orig. the
   same word as dik. See Dike.]
   1. A trench made in the earth by digging, particularly a
      trench for draining wet land, for guarding or fencing
      inclosures, or for preventing an approach to a town or
      fortress. In the latter sense, it is called also a moat
      or a fosse.
      [1913 Webster]

   2. Any long, narrow receptacle for water on the surface of
      the earth.
      [1913 Webster]

WordNet (r) 3.0 (2006):

ditch
    n 1: a long narrow excavation in the earth
    2: any small natural waterway
    v 1: forsake; "ditch a lover"
    2: throw away; "Chuck these old notes" [syn: chuck, ditch]
    3: sever all ties with, usually unceremoniously or
       irresponsibly; "The company dumped him after many years of
       service"; "She dumped her boyfriend when she fell in love
       with a rich man" [syn: dump, ditch]
    4: make an emergency landing on water
    5: crash or crash-land; "ditch a car"; "ditch a plane"
    6: cut a trench in, as for drainage; "ditch the land to drain
       it"; "trench the fields" [syn: trench, ditch]