Source : Webster's Revised Unabridged Dictionary (1913)

Supplement \Sup"ple*ment\, v. t. [imp. & p. p. {Supplemented};
   p. pr. & vb. n. {Supplementing}.]
   To fill up or supply by addition; to add something to.

         Causes of one kind must be supplemented by bringing to
         bear upon them a causation of another kind. --I.
                                                  Taylor.