The Collaborative International Dictionary of English v.0.48:

Lyra \Ly"ra\, n. [L. lyra, Gr. ?. See Lyre.]
   1. (Astron.) A northern constellation, the Harp, containing a
      white star of the first magnitude, called Alpha Lyr[ae],
      or Vega.
      [1913 Webster]

   2. (Anat.) The middle portion of the ventral surface of the
      fornix of the brain; -- so called from the arrangement of
      the lines with which it is marked in the human brain.
      [1913 Webster]

WordNet (r) 3.0 (2006):

Lyra
    n 1: a small constellation in the northern hemisphere near
         Cygnus and Draco; contains the star Vega