The Collaborative International Dictionary of English v.0.48:

Syrinx \Syr"inx\, n.; pl. Syringes. [NL., from Gr. ? a pipe.]
   1. (Mus.) A wind instrument made of reeds tied together; --
      called also pandean pipes.
      [1913 Webster]

   2. (Anat.) The lower larynx in birds.
      [1913 Webster]

   Note: In birds there are two laringes, an upper or true, but
         voiceless, larynx in the usual position behind the
         tongue, and a lower one, at or near the junction of the
         trachea and bronchi, which is the true organ of the
         voice.
         [1913 Webster]

WordNet (r) 3.0 (2006):

syrinx
    n 1: a primitive wind instrument consisting of several parallel
         pipes bound together [syn: panpipe, pandean pipe,
         syrinx]
    2: the vocal organ of a bird