I googled it and this is what I found from the Cleveland Clinic:
An esophagogastoduodenoscopy, EGD for short, is a simple procedure to examine your upper GI tract. The test involves an endoscope, a lighted camera on the end of a tube, which is passed down your throat to visualize your esophagus, stomach and duodenum. It’s also called an upper endoscopy exam.
Hope that helps!
P