Pronunciation: (im-pak'tid), [key]
1. tightly or immovably wedged in.
2. Dentistry.noting a tooth so confined in its socket as to be incapable of normal eruption.
3. driven together; tightly packed.
4. densely populated or crowded; overcrowded: an impacted school district.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.