Adenoids, AD uh noydz, also known as pharyngeal tonsils, are a mass of glandlike tissue normally present in the upper part of the throat, directly behind the nasal passages. A small amount of this tissue is always found in the throats of newborn babies. Usually it shrinks gradually and disappears by the time the child is 10 years old. But sometimes this shrinking process does not take place. Instead, the adenoid tissue increases in varying degrees to form a large growth. It is this growth that people commonly call "adenoids."