The Collaborative International Dictionary of English v.0.48:

Delphinus \Del*phi"nus\, n. [L., a dolphin, fr. Gr. delfi`s,
   delfi`n.]
   1. (Zool.) A genus of Cetacea, including the dolphin. See
      Dolphin, 1.
      [1913 Webster]

   2. (Astron.) The Dolphin, a constellation near the equator
      and east of Aquila.
      [1913 Webster] Delsarte

WordNet (r) 3.0 (2006):

Delphinus
    n 1: a constellation in the northern hemisphere near Pegasus and
         Aquila
    2: type genus of the Delphinidae [syn: Delphinus, genus
       Delphinus]