Source : Webster's Revised Unabridged Dictionary (1913)

Rebus \Re"bus\, v. t.
   To mark or indicate by a rebus.

         He [John Morton] had a fair library rebused with More
         in text and Tun under it.                --Fuller.

Rebus \Re"bus\, n.; pl. {Rebuses}. [L. rebus by things, abl. pl.
   of res a thing: cf. F. r['e]bus. Cf. 3d things, abl. pl. of
   res a thing: cf. F. r['e]bus. Cf. 3d {Real}.]
   1. A mode of expressing words and phrases by pictures of
      objects whose names resemble those words, or the syllables
      of which they are composed; enigmatical representation of
      words by figures; hence, a peculiar form of riddle made up
      of such representations.

   Note: A gallant, in love with a woman named Rose Hill, had,
         embroidered on his gown, a rose, a hill, an eye, a
         loaf, and a well, signifying, Rose Hill I love well.

   2. (Her.) A pictorial suggestion on a coat of arms of the
      name of the person to whom it belongs. See {Canting arms},
      under {Canting}.

Source : WordNet®

rebus
     n : a puzzle where you decode a message consisting of pictures
         representing syllables and words