foundational Definition

1a. The act of founding or establishing an institution, etc;
1b. The institution, etc founded or the fund providing for it.

Example: Paul was awarded a grant from the Smith Foundation
Thesaurus: organization, institution, endowment, institute, society, company, guild, trusteeship, corporation, association, charity.
2. The underground structure on which a building is supported and built.

Form: foundations (usually)
3. The basis on which a theory, etc rests or depends.

Thesaurus: basis, base, reason, justification.