Source : Webster's Revised Unabridged Dictionary (1913)

Eridanus \E*rid"a*nus\, n. [L., fr. Gr. ?, the Greek name of the
   River Po.] (Anat.)
   A long, winding constellation extending southward from Taurus
   and containing the bright star Achernar.

Source : WordNet®

Eridanus
     n : a constellation in the southern hemisphere near Fornax and
         Cetus