excavation

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun The act or process of excavating.
• noun A hole formed by excavating.

from The Century Dictionary.

• noun The act of making a thing hollow by removing the interior substance or part; the digging out of material, or its removal by any means, so as to form a cavity or hollow: as, the excavation of land by flowing water.
• noun A hollow or cavity formed by removing the interior substance: as, many animals burrow in excavations of their own forming.
• noun In engineering, an open cutting, as in a railway, in distinction from a tunnel.
• noun In zoology, a deep and somewhat irregular hollow with well-defined edges, as if a piece had been taken out of the surface.

from the GNU version of the Collaborative International Dictionary of English.

• noun The act of excavating, or of making hollow, by cutting, scooping, or digging out a part of a solid mass.
• noun A cavity formed by cutting, digging, or scooping.
• noun An uncovered cutting in the earth, in distinction from a covered cutting or tunnel.
• noun The material dug out in making a channel or cavity.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun uncountable The act of excavating, or of making hollow, by cutting, scooping, or digging out a part of a solid mass.
• noun countable A cavity formed by cutting, digging, or scooping.
• noun countable An uncovered cutting in the earth, in distinction from a covered cutting or tunnel.
• noun countable The material dug out in making a channel or cavity.
• noun uncountable Archaeological research that unearths buildings, tombs and objects of historical value.
• noun countable A site where an archaeological exploration is being carried out.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun the act of digging
• noun the act of extracting ores or coal etc from the earth
• noun the site of an archeological exploration
• noun a hole in the ground made by excavating