impaction

Meanings

1. A compression; the packing together of loose matter.
2. Something packed together tightly; a mass of densely-packed matter.
3. A solid, immobile bulk of stool.
4. The failure of a tooth to erupt into the dental arch, because of adjacent teeth, dense overlying bone, excessive soft tissue, or other factor.
5. The situation where an institute, usually a college or university, receives more applications from qualified applicants than the number of spaces available, meaning that meeting the minimum admission requirements does not guarantee acceptance.

Etymology

From Latin impingere (“to dash against, impinge”).