The Collaborative International Dictionary of English v.0.48:

Bird's nest \Bird's" nest`\, or Bird's-nest \Bird's-nest\, n.
   1. The nest in which a bird lays eggs and hatches her young.
      [1913 Webster]

   2. (Cookery) The nest of a small swallow (Collocalia
      nidifica and several allied species), of China and the
      neighboring countries, which is mixed with soups.
      [1913 Webster]

   Note: The nests are found in caverns and fissures of cliffs
         on rocky coasts, and are composed in part of alg[ae].
         They are of the size of a goose egg, and in substance
         resemble isinglass. See Illust. under Edible.
         [1913 Webster]

   3. (Bot.) An orchideous plant with matted roots, of the genus
      Neottia (Neottia nidus-avis).
      [1913 Webster]

   Bird's-nest pudding, a pudding containing apples whose
      cores have been replaced by sugar.

   Yellow bird's nest, a plant, the Monotropa hypopitys.
      [1913 Webster]