The Collaborative International Dictionary of English v.0.48:

Adulteration \A*dul`ter*a"tion\, n. [L. adulteratio.]
   1. The act of adulterating; corruption, or debasement (esp.
      of food or drink) by foreign mixture.
      [1913 Webster]

            The shameless adulteration of the coin. --Prescott.
      [1913 Webster]

   2. An adulterated state or product.
      [1913 Webster]

WordNet (r) 3.0 (2006):

adulteration
    n 1: being mixed with extraneous material; the product of
         adulterating [syn: adulteration, debasement]
    2: the act of adulterating (especially the illicit substitution
       of one substance for another)