The Collaborative International Dictionary of English v.0.48:

Ambuscade \Am`bus*cade"\, n. [F. embuscade, fr. It. imboscata,
   or Sp. emboscada, fr. emboscar to ambush, fr. LL. imboscare.
   See Ambush, v. t.]
   1. A lying in a wood, concealed, for the purpose of attacking
      an enemy by surprise. Hence: A lying in wait, and
      concealed in any situation, for a like purpose; a snare
      laid for an enemy; an ambush.
      [1913 Webster]

   2. A place in which troops lie hid, to attack an enemy
      unexpectedly. [R.] --Dryden.
      [1913 Webster]

   3. (Mil.) The body of troops lying in ambush.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Ambuscade \Am`bus*cade"\, v. t. [imp. & p. p. Ambuscaded; p.
   pr. & vb. n. Ambuscading.]
   1. To post or conceal in ambush; to ambush.
      [1913 Webster]

   2. To lie in wait for, or to attack from a covert or lurking
      place; to waylay.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Ambuscade \Am`bus*cade"\, v. i.
   To lie in ambush.
   [1913 Webster]

WordNet (r) 3.0 (2006):

ambuscade
    n 1: the act of concealing yourself and lying in wait to attack
         by surprise [syn: ambush, ambuscade, lying in wait,
         trap]
    v 1: wait in hiding to attack [syn: ambush, scupper,
         bushwhack, waylay, lurk, ambuscade, lie in wait]