noun

• (linguistics) A pictographic component of a compound character (e.g. sinograph) used to hint at the pronunciation of the compound.
• (specifically, heraldry) An arrangement of pictures on a coat of arms which suggests the name of the person to whom it belongs.
  "The prior [Will Bolton] used to come out here to hunt in summer and recreate himself, and his rebus—a barrel or tun shot through with a crossbow bolt—is set into the garden walls."
• (crosswording) A type of crossword puzzle in which some squares contain entire words, or symbols representing words, instead of single letters.
  "Instead of spelling out card suits, for example, perhaps the constructor inserted a "rebus," or picture icon for clubs, hearts, spades, or diamonds in one answer box."