Definition of Peritonsillar abscess

Peritonsillar abscess: A collection of pus behind the tonsils that pushes one of the tonsils toward the uvula (the prominent soft tissue dangling from the back of the palate in the back of the mouth). A peritonsillar abscess is generally very painful and is usually associated with a decreased ability to open the mouth. If left untreated, the infection can spread deep in the neck causing airway obstruction and life-threatening complications.