Which condition is characterized by chronic acid reflux?

Chronic acid reflux is primarily characterized by gastroesophageal reflux disease (GERD). This condition occurs when stomach acid or bile flows back into the esophagus, leading to irritation and inflammation of the esophageal lining. The symptoms of GERD often include heartburn, regurgitation, and discomfort in the chest or throat, which are direct results of the backflow of contents from the stomach.

In contrast, ulcerative colitis and peptic ulcer disease involve inflammation in different parts of the digestive system, primarily the colon and stomach respectively, rather than the esophagus. Cholecystitis is an inflammation of the gallbladder and is not associated with acid reflux. Thus, GERD is the specific condition that encompasses the chronic nature of acid reflux, making it the correct answer.