The Collaborative International Dictionary of English v.0.48:

manila paper \manila paper\ n.
   A durable brown or buff paper or thin cardboard with a smooth
   light brown finish, made of Manila hemp, and used as a
   wrapping paper, or as a cheap printing and writing paper. The
   name is also given to inferior papers, made of other fiber.

   Syn: manila, manila paper, manilla, manilla paper.
        [1913 Webster]

WordNet (r) 3.0 (2006):

manila paper
    n 1: a strong paper or thin cardboard with a smooth light brown
         finish made from e.g. Manila hemp [syn: manila, manila
         paper, manilla, manilla paper]