Source : Webster's Revised Unabridged Dictionary (1913)

Impacted \Im*pact"ed\, a.
   Driven together or close.

   {Impacted fracture} (Surg.), a fracture in which the
      fragments are driven into each other so as to be
      immovable.

Impact \Im*pact"\, v. t. [imp. & p. p. {Impacted}; p. pr. & vb.
   n. {Impacting}.] [L. impactus, p. p. of impingere to push,
   strike against. See {Impinge}.]
   To drive close; to press firmly together: to wedge into a
   place. --Woodward.

Source : WordNet®

impacted
     adj : wedged or packed in together; "an impacted tooth" [syn: {wedged}]