superstructure

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

• noun A physical or conceptual structure extended or developed from a basic form.
• noun The part of a building or other structure above the foundation.
• noun The parts of a ship's structure above the main deck.
• noun The rails, sleepers, and other parts of a railway.
• noun In Marxist theory, the ideologies or institutions of a society as distinct from the basic processes and direct social relations of material production and economics.

from The Century Dictionary.

• noun Any structure built on something else; particularly, an edifice in relation to its foundation.
• noun Hence, anything erected on a foundation or basis.
• noun In railway engin., the sleepers, rails, and fastenings of a railway, in contradistinction to road-bed.

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

• noun (Arch.) Any material structure or edifice built on something else; that which is raised on a foundation or basis.
• noun (Railway Engin.) The sleepers, and fastenings, in distinction from the roadbed.

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

• noun nautical Any structure built above the top full deck. (FM 55-501).
• noun Any material structure or edifice built on something else; that which is raised on a foundation or basis
• noun all that part of a building above the basement. Also used figuratively.
• noun UK (railroad) The sleepers, and fastenings, in distinction from the roadbed.

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

• noun structure consisting of the part of a ship above the main deck