The Collaborative International Dictionary of English v.0.48:

Leo \Le"o\ (l[=e]"[=o]), n. [L. See Lion.] (Astron.)
   1. The Lion, the fifth sign of the zodiac, marked thus
      [[Leo]] in almanacs.
      [1913 Webster]

   2. A northern constellation east of Cancer, containing the
      bright star Regulus at the end of the handle of the
      Sickle.
      [1913 Webster]

   Leo Minor, a small constellation between Leo and the Great
      Bear.
      [1913 Webster]