An endoscopy (looking inside) is a procedure used in medicine to look inside the body.The endoscopy procedure uses an endoscope to examine the interior of a hollow organ or cavity of the body. Unlike many other medical imaging techniques, endoscopes are inserted directly into the organ.

There are many types of endoscopies. Depending on the site in the body and type of procedure, an endoscopy may be performed by either a doctor or a surgeon. A patient may be fully conscious or anaesthetised during the procedure. Most often, the term endoscopy is used to refer to an examination of the upper part of the gastrointestinal tract, known as an esophagogastroduodenoscopy.

For nonmedical use, similar instruments are called borescopes.-Courtesy – Wikipedia