GER:	the passage of gastric contents into the esophagus with or without regurgitation and vomiting.
GERD:	when GER leads to troublesome symptoms and/or complications.
Refractory GERD:	GERD not responding to optimal treatment after eight weeks.
Optimal Therapy:	Maximum pharmacologic and/or non-pharmacologic therapy based on the region of practice of the subspecialist
Infants:	under 12 months
Children:	12 months to 18 years
Regurgitation:	the passage of refluxed contents into the pharynx, mouth or from The mouth. Other terms such as ‘spitting-up’, ‘posseting’, and ‘spilling’ are considered equivalent to regurgitation.
Vomiting:	a coordinated autonomic and voluntary motor response, causing forceful expulsion of gastric contents through the mouth.
Rumination:	effortless regurgitation of recently ingested food into the mouth With subsequent mastication and re-swallowing.
Rumination syndrome:	distinct clinical entity in which rumination follows in minutes after ingestion of a meal, does not occur during sleep and does not respond to standard treatment for gastro-esophageal reflux. In infant rumination syndrome, this involves repetitive contractions of the abdominal wall muscles, diaphragm and tongue.(301, 302)
Reflux hypersensitivity:	patients with esophageal symptoms (heartburn or chest pain) who lack evidence of reflux on endoscopy or abnormal acid burden on reflux monitoring, but do have evidence that reflux events trigger symptoms.
Functional Heartburn:	patients with esophageal symptoms (heartburn or chest pain) who lack evidence of reflux on endoscopy or abnormal acid burden on reflux monitoring, and do not have evidence that symptoms are triggered by reflux events.
Non-erosive reflux disease (NERD):	patients with esophageal symptoms who lack evidence of reflux on endoscopy but do have and abnormal acid burden that may or may not trigger symptoms.