The Collaborative International Dictionary of English v.0.48:

Yankee-Doodle \Yan`kee-Doo"dle\, n.
   1. The name of a tune adopted popularly as one of the
      national airs of the United States.
      [1913 Webster]

   2. Humorously, a Yankee.
      [1913 Webster]

            We might have withheld our political noodles
            From knocking their heads against hot
            Yankee-Doodles.                       --Moore.
      [1913 Webster]

WordNet (r) 3.0 (2006):

Yankee-Doodle
    n 1: an American (especially to non-Americans) [syn: Yankee,
         Yank, Yankee-Doodle]