Source : Webster's Revised Unabridged Dictionary (1913)

Grapnel \Grap"nel\, n. [OE. grapenel, dim. fr. F. grappin the
   grapple of a ship; of German origin. See {Grape}.] (Naut.)
   A small anchor, with four or five flukes or claws, used to
   hold boats or small vessels; hence, any instrument designed
   to grapple or hold; a grappling iron; a grab; -- written also
   grapline, and crapnel.

Source : WordNet®

grapnel
     n 1: a tool consisting of several hooks for grasping and holding;
          often thrown with a rope [syn: {grapple}, {grappler}, {grappling
          hook}, {grappling iron}]
     2: a light anchor for small boats [syn: {grapnel anchor}]