Tonsillitis refers to the infection of tonsils - they become inflamed and swollen. Tonsils are located at the entrance to the throat on both sides. It can happen at any age, though the very young and the very old are affected more often than the rest of the population. The term "acute" simply means the disease comes suddenly and lasts a short time. "Chronic" means the disease lasts for a longer time.
Attribution: Avallain