Source : Webster's Revised Unabridged Dictionary (1913)

Corbiestep \Cor"bie*step`\, n. (Arch.)
   One of the steps in which a gable wall is often finished in
   place of a continuous slope; -- also called {crowstep}.

Source : WordNet®

corbiestep
     n : (architecture) a step or step-like projection on the top of
         a gable wall [syn: {corbel step}, {corbie-step}, {crow
         step}]