Complete Denture is a dental prosthesis that replaces all of the natural dentition and associated structures of the maxilla or mandible. It is entirely supported by tissues (mucous membrane, connective tissues and underlying bone).
Reference
Carr A B, McGivney G P, Brown D T: McCracken’s Removable Partial Denture, ed 11, 2005, Mosby.
[...] Complete Denture Prosthodontics involves the replacement of the lost natural dentition and associated structures of the maxilla and mandible for patients who have lost all their remaining natural teeth or roots to provide more favorable support and stability for the resultant denture, with the preservation of alveolar bone being perhaps a far more important concurrent end result. [...]