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]