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.
      [1913 Webster]

   2. To form by hollowing; to shape, as a cavity, or anything
      that is hollow; as, to excavate a canoe, a cellar, a
      channel.
      [1913 Webster]

   3. (Engin.) To dig out and remove, as earth.
      [1913 Webster]

            The material excavated was usually sand. --E. L.
                                                  Corthell.
      [1913 Webster]

   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]

Moby Thesaurus II by Grady Ward, 1.0:

84 Moby Thesaurus words for "excavate":
   avulse, bore, bring to light, bring up, burrow, clear, countersink,
   cut out, deepen, delve, depress, deracinate, dig, dig out, dig up,
   dike, disclose, disentangle, disinter, dive, draw, draw out,
   dredge, dredge up, drill, drive, eradicate, evolve, evulse, excise,
   exhume, expose, exsect, extract, extricate, ferret out, fish up,
   furrow, get out, gouge, gouge out, groove, grub, grub up,
   hollow out, lay bare, lower, mine, pick out, pluck out, pluck up,
   pull, pull out, pull up, quarry, rake out, remove, reveal, rip out,
   root out, root up, sap, scoop, scoop out, scrabble, scrape,
   scratch, shovel, sink, spade, take out, tear out, trench, trough,
   tunnel, turn up, uncover, unearth, unravel, uproot, weed out,
   withdraw, worm out, wrest out