Source : Webster's Revised Unabridged Dictionary (1913)

Poleax \Pole"ax`\, Poleaxe \Pole"axe`\, n. [OE. pollax; cf. OD.
   pollexe. See {Poll} head, and Ax.]
   Anciently, a kind of battle-ax with a long handle; later, an
   ax or hatchet with a short handle, and a head variously
   patterned; -- used by soldiers, and also by sailors in
   boarding a vessel.

Source : WordNet®

poleax
     n 1: an ax used to slaughter cattle; has a hammer opposite the
          blade [syn: {poleaxe}]
     2: a battle ax used in the Middle Ages; a long handled ax and a
        pick [syn: {poleaxe}]
     v : fell with or as if with a poleax [syn: {poleaxe}]