Inflammation of the gallbladder, usually from gallstones blocking the bile duct or from bacterial infection.
From Greek 'chole' (bile) + 'kystis' (bladder) + '-itis' (inflammation). The fully Latinized form became standard in modern medical terminology by the 1800s.
This is probably the most common gallbladder diagnosis—acute cholecystitis sends thousands to the emergency room yearly, and it's why learning this term is practically useful rather than just academic.
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