The esophagus (American English) or oesophagus (British English), commonly known as the foodpipe or gullet, is an organ in vertebrates which consists of a tube through which food passes, aided by peristaltic contractions, from the pharynx to the stomach. In humans, the esophagus is usually 18–25 centimeters (cm) long. During swallowing the epiglottis tilts backwards to prevent food from going down the larynx. The esophagus travels behind the trachea and heart, passes through the diaphragm and empties into the cardia of the stomach. The word esophagus derives from the Greek word oisophagos, which means "to carry to eat."