What is the definition or description of: acid reflux?

Acid reflux: Acid reflux is defined as the presence of acidic gastric contents in the esophagus causing irritation. It's cause is blamed on the a lax gastroesophageal shpincter that permits usch regurgitation.

Heartburn: Technically called GERD, acid reflux is the presence of acidic stomach contents in the esophagus. The acid irritates the esophagus causing heartburn symptoms. The regurgitation or reflux can vary greatly as can the symptoms. Blocking stomach acid with medications can alleviate the burning but medication cannot stop the reflux. Complicated GERD requires surgical treatment for a definitive cure.