Source : Webster's Revised Unabridged Dictionary (1913)

Tush \Tush\, interj.
   An exclamation indicating check, rebuke, or contempt; as,
   tush, tush! do not speak of it.

         Tush, say they, how should God perceive it? --Bk. of
                                                  Com. Prayer
                                                  (Ps. lxxiii.
                                                  11).

Tush \Tush\, n. [OE. tusch, AS. tusc; akin to OFries. tusk,
   tusch, and probably to AS. t[=o][eth] tooth. See {Tooth}, and
   cf. {Tusk}.]
   A long, pointed tooth; a tusk; -- applied especially to
   certain teeth of horses.

Source : WordNet®

tush
     n : the fleshy part of the human body that you sit on; "he
         deserves a good kick in the butt"; "are you going to sit
         on your fanny and do nothing?" [syn: {buttocks}, {nates},
          {arse}, {butt}, {backside}, {bum}, {buns}, {can}, {fundament},
          {hindquarters}, {hind end}, {keister}, {posterior}, {prat},
          {rear}, {rear end}, {rump}, {stern}, {seat}, {tail}, {tail
         end}, {tooshie}, {bottom}, {behind}, {derriere}, {fanny},
          {ass}]