Source : Webster's Revised Unabridged Dictionary (1913)

Multiplex \Mul"ti*plex\, a. [L. multiplex, -plicis. See
   {Multiply}.]
   Manifold; multiple.

Source : WordNet®

multiplex
     adj 1: many and varied; having many features or forms; "manifold
            reasons"; "our manifold failings"; "manifold
            intelligence"; "the multiplex opportunities in high
            technology" [syn: {manifold}]
     2: having many parts or aspects; "the multiplex problem of drug
        abuse"

multiplex
     n : communicates two or more signals over a common channel