Which condition is characterized by inflammation of the esophagus?

The condition characterized by inflammation of the esophagus is esophagitis. This condition can result from various factors including infections, irritants such as certain medications, or acid reflux. The inflammation can lead to symptoms such as difficulty swallowing, chest pain, and heartburn.

In contrast, gastritis refers to the inflammation of the stomach lining rather than the esophagus, making it distinct from esophagitis. Diverticulosis involves the formation of small pouches in the colon and does not involve the esophagus. Cholecystitis, on the other hand, involves inflammation of the gallbladder and is unrelated to the esophageal structure. Thus, the clear association of esophagitis with inflammation specifically targeting the esophagus solidifies it as the correct answer.