It comes from the Greek word "ἔνδον" (endon), meaning "within."
Here are some examples of words using the prefix "endo":
* Endocrine: Relating to glands that secrete hormones directly into the bloodstream.
* Endometriosis: A condition where tissue similar to the lining of the uterus grows outside the uterus.
* Endoskeleton: The internal skeleton of an animal.
* Endothermic: Referring to animals that generate their own body heat.
* Endoscopy: A medical procedure that uses a long, thin tube with a camera to view the inside of the body.