Acid Reflux and GERD are tied closely together. Here’s an easy way to know the difference: Acid Reflux occurs when the acid in your stomach backs up, or refluxes, into your esophagus, causing heartburn. And Gastro-Esophageal Reflux Disease (GERD) is chronic or recurring acid reflux.
https://www.tums.com/heartburn-information/acid-reflux-gerd/
Heartburn Info