[1] : The Collaborative International Dictionary of English v.0.48

impaction \impac"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

[2] : WordNet (r) 2.0

impaction
     n 1: the condition of being pressed closely together and firmly
          fixed
     2: a disorder in which feces are impacted in the lower colon
     3: a disorder in which a tooth is so crowded in its socket that
        it cannot erupt normally syn: impacted tooth
     4: a sharp collision produced by striking or dashing against
        something syn: impingement
see also:
impacted tooth impingement 

Impaction >> I Words
Impaction, definition of term: Impaction
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