heartburn

noun

heart·​burn ˈhärt-ˌbərn 

plural heartburns

: a burning discomfort behind the lower part of the sternum due especially to the backward flow of the acidic contents of the stomach into the esophagus

In any given month, about one-quarter of Americans suffer from heartburn, which is caused by reflux, or backward flow, of stomach acid into the esophagus.

—Clyde M. Burnham

Heartburn—painful reflux of stomach acid—can occur in a person with a perfectly intact esophagus.

—Paul G. Donohue

see acid reflux

Examples of heartburn in a Sentence

I like spicy food, but it gives me heartburn.

Recent Examples on the Web

Like much of the talk at City Hall, the library’s outlook is tied to Boise’s expansion, and the heartburn that arises when the needs of residents conflict with future demand from people who might be here soon. —Mark Dee, Idaho Statesman, 25 Feb. 2026

Common side effects can include nausea, vomiting, diarrhea, abdominal pain, indigestion, fatigue and heartburn. —Shafiq Najib, ABC News, 23 Feb. 2026

And the biggest side effect for me was heartburn. —Renée Onque, CNBC, 23 Feb. 2026

But don’t go overboard, Crichton said; consuming more than that could cause mild but uncomfortable side effects like heartburn, reflux and indigestion. —The New York Times News Service Syndicate, San Diego Union-Tribune, 10 Feb. 2026

Word History

First Known Use

15th century, in the meaning defined above

Rhymes for heartburn

• adjourn
• concern
• decern
• discern
• downturn
• extern
• interne
• nocturne
• return
• sunburn
• unworn
• upturn

Kids Definition

heartburn

noun

heart·​burn -ˌbərn 

: a burning discomfort seeming to occur in the area of the heart and usually due to spasms which pass acid from the stomach into the esophagus

Medical Definition

heartburn

noun

heart·​burn -ˌbərn 

: a burning discomfort behind the lower part of the sternum due especially to the backward flow of the acidic contents of the stomach into the esophagus

called also cardialgia, pyrosis

see acid reflux compare water brash