Simple Definition:

Endoscopy is a medical procedure that uses a flexible tube with a camera at the end to examine the inside of your body. This helps doctors see and diagnose problems in areas like the digestive system [the organs that break down food in your body] or the lungs [the organs that help you breathe].

For example, if a person has stomach pain, a doctor might perform an endoscopy to look inside the stomach and see if there are any issues, like ulcers [sores in the stomach] or inflammation [swelling]. During the procedure, the doctor inserts the tube through the mouth and guides it down the throat into the stomach.

Very Simple Definition:

Endoscopy is a medical procedure where a doctor uses a long tube with a camera to look inside your body. It helps the doctor find out what might be wrong inside you.

For example, if your stomach hurts, the doctor might use a long tube with a camera to look inside your stomach and see why it is hurting.