The Collaborative International Dictionary of English v.0.48:

shtick \shtick\, shtik \shtik\(sht[i^]k), n. [Yiddish, pranks;
   fr. MHG st["u]cke, pieces.]
   1. A person's special talent, line of business, or habitual
      activity.
      [PJC]

   2. (Show business) A comic routine or a specific gag inserted
      in a show for laughs.
      [PJC]

WordNet (r) 3.0 (2006):

shtick
    n 1: (Yiddish) a little; a piece; "give him a shtik cake"; "he's
         a shtik crazy"; "he played a shtik Beethoven" [syn:
         shtik, shtick, schtik, schtick]
    2: (Yiddish) a contrived and often used bit of business that a
       performer uses to steal attention; "play it straight with no
       shtik" [syn: shtik, schtik, shtick, schtick]
    3: (Yiddish) a prank or piece of clowning; "his shtik made us
       laugh" [syn: shtik, schtik, shtick, schtick]
    4: (Yiddish) a devious trick; a bit of cheating; "how did you
       ever fall for a shtik like that?" [syn: shtik, schtik,
       shtick, schtick]

Moby Thesaurus II by Grady Ward, 1.0:

29 Moby Thesaurus words for "shtick":
   act, afterpiece, bit, chaser, curtain, curtain call,
   curtain raiser, divertimento, divertissement, epilogue, exode,
   exodus, expository scene, finale, hoke act, interlude, intermezzo,
   intermission, introduction, number, prologue, routine, scene,
   sketch, skit, song and dance, stand-up comedy act, striptease,
   turn