a burning sensation beneath the breastbone resulting from a spastic reflux of stomach acid, food, etc. into the esophagus; pyrosis; brash
See heartburn in American Heritage Dictionary 4
A burning sensation, usually centered in the middle of the chest near the sternum, caused by the reflux of acidic stomach fluids that enter the lower end of the esophagus. Also called acid reflux, cardialgia, pyrosis.