Definitions of heartburn

1. a painful burning sensation in the chest caused by gastroesophageal reflux ( backflow from the stomach irritating the esophagus); symptomatic of an ulcer or a diaphragmatic hernia or other disorder

2. A burning in the stomach due to acidity.

3. A burning sensation in the esophagus, due to acidity of the stomach.

4. Pain, heat, and uneasiness about the region of the stomach.