The Collaborative International Dictionary of English v.0.48:
Serpens \Ser"pens\, n. [L. See Serpent.] (Astron.) A constellation represented as a serpent held by Serpentarius. [1913 Webster]WordNet (r) 3.0 (2006):
Serpens n 1: a constellation in the equatorial region of the northern hemisphere near Ophiuchus and Corona Borealis