basis

/ˈbeɪsɪs/
noun
  1. The main or most important reason or fact that supports something.
    • The evidence provided a solid basis for the court's decision.
    • Her argument had no basis in fact.
    • Trust is the basis of any strong friendship.
  2. The way something is done or organized; a system or method.
    • The charity operates on a volunteer basis.
    • They meet on a weekly basis to discuss progress.
    • He works on a freelance basis, taking projects as they come.
  3. The starting point or foundation from which something develops.
    • The agreement served as a basis for future negotiations.
    • These early experiments formed the basis for modern medicine.
    • The first chapter lays the basis for the rest of the book.