The Collaborative International Dictionary of English v.0.48:

Ophidian \O*phid"i*an\, n. [Cf. F. ophidien.] (Zool.)
   One of the Ophidia; a snake or serpent.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Ophidian \O*phid"i*an\, a. [Cf. F. ophidien.] (Zool.)
   Of or pertaining to the Ophidia; belonging to serpents.
   [1913 Webster]

WordNet (r) 3.0 (2006):

ophidian
    n 1: limbless scaly elongate reptile; some are venomous [syn:
         snake, serpent, ophidian]