groundwork

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

• noun A foundation; a basis. synonym: base.

from The Century Dictionary.

• noun That which forms the foundation of something; the foundation or basis; the fundamental part, principle, or motive: used of both material and immaterial things.

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

• noun That which forms the foundation or support of anything; the basis; the essential or fundamental part; first principle.

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

• noun The foundation; the basic or fundamental parts that support or allow for the rest.

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

• noun lowest support of a structure
• noun preliminary preparation as a basis or foundation
• noun the fundamental assumptions from which something is begun or developed or calculated or explained