Source : Webster's Revised Unabridged Dictionary (1913)

Ambush \Am"bush\, n. [F. emb[^u]che, fr. the verb. See {Ambush},
   v. t.]
   1. A disposition or arrangement of troops for attacking an
      enemy unexpectedly from a concealed station. Hence: Unseen
      peril; a device to entrap; a snare.

            Heaven, whose high walls fear no assault or siege Or
            ambush from the deep.                 --Milton.

   2. A concealed station, where troops or enemies lie in wait
      to attack by surprise.

            Bold in close ambush, base in open field. --Dryden.

   3. The troops posted in a concealed place, for attacking by
      surprise; liers in wait. [Obs.]

            The ambush arose quickly out of their place. --Josh.
                                                  viii. 19.

   {To lay an ambush}, to post a force in ambush.