The Collaborative International Dictionary of English v.0.48:

Excavation \Ex`ca*va"tion\, n. [L. excavatio: cf. F.
   excavation.]
   1. The act of excavating, or of making hollow, by cutting,
      scooping, or digging out a part of a solid mass.
      [1913 Webster]

   2. A cavity formed by cutting, digging, or scooping. "A
      winding excavation." --Glover.
      [1913 Webster]

   3. (Engin.)
      (a) An uncovered cutting in the earth, in distinction from
          a covered cutting or tunnel.
      (b) The material dug out in making a channel or cavity.
          [1913 Webster]

                The delivery of the excavations at a distance of
                250 feet.                         --E. L.
                                                  Corthell.
          [1913 Webster]

WordNet (r) 3.0 (2006):

excavation
    n 1: the act of digging; "there's an interesting excavation
         going on near Princeton" [syn: excavation, digging,
         dig]
    2: the site of an archeological exploration; "they set up camp
       next to the dig" [syn: dig, excavation, archeological
       site]
    3: a hole in the ground made by excavating
    4: the act of extracting ores or coal etc from the earth [syn:
       mining, excavation]