The Collaborative International Dictionary of English v.0.48:

Parmesan \Par`me*san"\, a. [F. parmesan, It. parmigiano.]
   1. Of or pertaining to Parma in Italy.
      [1913 Webster]

   2. Parmesan cheese.
      [PJC]

   Parmesan cheese, a kind of cheese of a rich flavor, though
      from skimmed milk, made in Parma, Italy.
      [1913 Webster]

WordNet (r) 3.0 (2006):

Parmesan
    n 1: hard dry sharp-flavored Italian cheese; often grated