Endoscope is endoscopy and colonoscopy equipment that is equipped with a medical grade tube (a light and camera attach on it) that is used by doctors to view images of your digestive tract to examine esophagus, stomach, and upper part of the small intestine, area of the intestine etc. It is also known as colonoscope because to examine the area of  intestine, doctors inserts it into Colon and this process called colonoscopy.