acid reflux

noun

: backward flow of the acidic contents of the stomach into the esophagus that is due to malfunctioning of a sphincter at the lower end of the esophagus and that results especially in heartburn : gastroesophageal reflux

a medication for acid reflux

Acid reflux is the backflow of stomach contents into the esophagus. The feeling of acid reflux is heartburn: a mild burning sensation in the mid-chest …

—The Tennessee Tribune

Acid reflux occurs when the valve between your esophagus and stomach doesn't close properly, allowing stomach acid to wash back up through your esophagus …

—Miriam Jones Bradley

Examples of acid reflux in a Sentence

Recent Examples on the Web

This backwash, also known as acid reflux, irritates the lining of your esophagus. —Elizabeth Ayoola, Essence, 3 July 2025

Treat Acid Reflux and GERD Occasional acid reflux or its chronic counterpart, gastroesophageal reflux disease (GERD), can cause bad breath. —Amber J. Tresca, Verywell Health, 28 Mar. 2025

So can acid reflux or eating things that are particularly hot or spicy. —Bruce Y. Lee, Forbes.com, 14 June 2025

Acid Reflux Alongside dry mouth, acid reflux is a common Ozempic side effect that can indirectly damage your teeth, said Garcia-Webb. —Kathleen Ferraro, Verywell Health, 6 June 2025

Word History

First Known Use

1960, in the meaning defined above

Medical Definition

acid reflux

noun

: backward flow of the acidic contents of the stomach into the esophagus that is due to malfunctioning of a sphincter at the lower end of the esophagus and that results especially in heartburn : gastroesophageal reflux

… people who report experiencing at least weekly symptoms of acid reflux have substantially higher risks of BE [=Barrett's esophagus] than those with less frequent episodes. Moreover, we found that symptoms of acid reflux experienced at older ages conferred substantially higher risks of BE than symptoms at younger ages …

—Kylie J. Smith et al., Cancer Epidemiology, Biomarkers & Prevention