Source : Webster's Revised Unabridged Dictionary (1913)

Impingement \Im*pinge"ment\, n.
   The act of impinging.

Source : WordNet®

impingement
     n 1: influencing strongly; "they resented the impingement of
          American values on European culture" [syn: {encroachment},
           {impact}]
     2: a sharp collision produced by striking or dashing against
        something [syn: {impaction}]