tonsils, name commonly referring to the palatine tonsils, two ovoid masses of lymphoid tissue situated on either side of the throat at the back of the tongue. The pharyngeal tonsils, or adenoids, are masses of similar tissue located in the nasopharynx, and the lingual tonsils are rounded masses of tissue on the back of the tongue. The tonsils act as a filter against disease organisms. However, they often become a site of infection, a condition known as tonsillitis, and sometimes become enlarged. This condition is more prevalent during childhood, since tonsil tissue tends to regress with age. Tonsillectomy, the removal of the tonsils, is sometimes advised if frequent inflammation poses a threat to health. Tonsilloliths, or tonsil stones, sometimes form in the tonsils when dead cells and other debris that has accumulated calcifies; most common in persons with chronic tonsillitis, tonsil stones can cause difficulty in swallowing, halitosis (bad breath), and ear pain. Troublesome stones can be extracted; the only certain means of preventing recurrence is tonsillectomy. See respiration.