The Collaborative International Dictionary of English v.0.48:

Nankeen \Nan*keen"\, n. [So called from its being originally
   manufactured at Nankin (Nanjing), in China.] [Written also
   nankin.]
   1. A species of cloth, of a firm texture, originally brought
      from China, made of a species of cotton (Gossypium
      religiosum) that is naturally of a brownish yellow color
      quite indestructible and permanent.
      [1913 Webster]

   2. An imitation of this cloth by artificial coloring.
      [1913 Webster]

   3. pl. Trousers made of nankeen. --Ld. Lytton.
      [1913 Webster]

   Nankeen bird (Zool.), the Australian night heron
      (Nycticorax Caledonicus); -- called also quaker.
      [1913 Webster]

WordNet (r) 3.0 (2006):

nankeen
    n 1: a durable fabric formerly loomed by hand in China from
         natural cotton having a yellowish color