The Collaborative International Dictionary of English v.0.48:

Morpheus \Mor"pheus\ (m[^o]r"f[=u]s or m[^o]r"f[-e]*[u^]s), n.
   [L., fr. Gr. Morfey`s prop., the fashioner or molder, because
   of the shapes he calls up before the sleeper, fr. morfh`
   form, shape.] (Class. Myth.)
   The god of dreams.
   [1913 Webster]

WordNet (r) 3.0 (2006):

Morpheus
    n 1: the Roman god of sleep and dreams