Gastroesophageal refers to the stomach and esophagus. Reflux means to return or flow back. Gastroesophageal reflux disease or GERD is a set of conditions, where the lower esophageal sphincter (LES) is affected when the contents of the stomach flows back to the esophagus. In usual digestion process, the lower esophageal sphincter unfastens to let food to pass into stomach and shuts to ... https://www.reddit.com/r/Gastroenterology/comments/1cif6ul/what_is_the_difference_between_reflux_esophagitis/