The Collaborative International Dictionary of English v.0.48:

Firedrake \Fire"drake`\ (f[imac]r"dr[=a]k`), n. [AS.
   f[=y]rdraca; f[=y]r fire + draca a dragon. See Fire, and
   Drake a dragon.] [Obs.]
   1. A fiery dragon. --Beau. & Fl.
      [1913 Webster]

   2. A fiery meteor; an ignis fatuus; a rocket.
      [1913 Webster]

   3. A worker at a furnace or fire. --B. Jonson.
      [1913 Webster]

WordNet (r) 3.0 (2006):

firedrake
    n 1: a creature of Teutonic mythology; usually represented as
         breathing fire and having a reptilian body and sometimes
         wings [syn: dragon, firedrake]