endoskeleton

/ˌɛndoʊˈskɛlətən/
noun
  1. An internal skeleton, such as the bones of vertebrates, that supports the body and protects internal organs.
    • The endoskeleton provides a framework for muscles to attach and move the body.
    • The human endoskeleton is made up of over 200 bones.
    • A shark's endoskeleton is made of cartilage instead of bone.
Antonyms