'Impaction' definitions:

Definition of 'impaction'

From: WordNet
noun
The condition of being pressed closely together and firmly fixed
noun
A disorder in which feces are impacted in the lower colon
noun
A disorder in which a tooth is so crowded in its socket that it cannot erupt normally [syn: impaction, impacted tooth]
noun
A sharp collision produced by striking or dashing against something [syn: impingement, impaction]

Definition of 'Impaction'

From: GCIDE
  • Impaction \Im*pac"tion\, n. [L. impactio a striking : cf. F. impaction.]
  • 1. (Surg.) The driving of one fragment of bone into another so that the fragments are not movable upon each other; as, impaction of the skull or of the hip. [1913 Webster]
  • 2. An immovable packing; (Med.), a lodgment of something in a strait or passage of the body; as, impaction of the fetal head in the strait of the pelvis; impaction of food or feces in the intestines of man or beast. [1913 Webster]