The Collaborative International Dictionary of English v.0.48:

Americana \Americana\ ([.a]*m[~e]r`[i^]*k[a^]n"[.a]), n.
   1. any artifact (such a books or furniture or art) that is
      distinctive to America.
      [WordNet 1.5]

WordNet (r) 3.0 (2006):

Americana
    n 1: any artifact (such as books or furniture or art) that is
         distinctive of America