'Endoskeleton' definitions:

Definition of 'endoskeleton'

From: WordNet
noun
The internal skeleton; bony and cartilaginous structure (especially of vertebrates)

Definition of 'Endoskeleton'

From: GCIDE
  • Endoskeleton \En`do*skel"e*ton\, n. [Endo- + skeleton.] (Anat.) The bony, cartilaginous, or other internal framework of an animal, as distinguished from the exoskeleton. [1913 Webster]