The Collaborative International Dictionary of English v.0.48:

Excavate \Ex"ca*vate\, v. t. [imp. & p. p. Excavated; p. pr. &
   vb. n. Excavating.] [L. excavatus, p. p. of excavare to
   excavate; ex out + cavare to make hollow, cavus hollow. See
   Cave.]
   1. To hollow out; to form cavity or hole in; to make hollow
      by cutting, scooping, or digging; as, to excavate a ball;
      to excavate the earth.
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   2. To form by hollowing; to shape, as a cavity, or anything
      that is hollow; as, to excavate a canoe, a cellar, a
      channel.
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   3. (Engin.) To dig out and remove, as earth.
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            The material excavated was usually sand. --E. L.
                                                  Corthell.
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   Excavating pump, a kind of dredging apparatus for
      excavating under water, in which silt and loose material
      mixed with water are drawn up by a pump. --Knight.
      [1913 Webster]

WordNet (r) 3.0 (2006):

excavate
    v 1: recover through digging; "Schliemann excavated Troy";
         "excavate gold" [syn: excavate, unearth]
    2: find by digging in the ground; "I dug up an old box in the
       garden" [syn: excavate, dig up, turn up]
    3: form by hollowing; "Carnegie had a lake excavated for
       Princeton University's rowing team"; "excavate a cavity"
    4: remove the inner part or the core of; "the mining company
       wants to excavate the hillside" [syn: excavate, dig,
       hollow]