Source : Webster's Revised Unabridged Dictionary (1913)

Symphonious \Sym*pho"ni*ous\, a. [From {Symphony}.]
   1. Agreeing in sound; accordant; harmonious.

            Followed with acclamation and the sound Symphonious
            of ten thousand harps.                --Milton.

   2. (Mus.) Symphonic.

Source : WordNet®

symphonious
     adj : harmonious in sound; "the symphonic hum of a million
           insects" [syn: {symphonic}]