Source : Webster's Revised Unabridged Dictionary (1913)

Gunwale \Gun"wale\, n. [Gun + wale. So named because the upper
   guns were pointed from it.] (Naut.)
   The upper edge of a vessel's or boat's side; the uppermost
   wale of a ship (not including the bulwarks); or that piece of
   timber which reaches on either side from the quarter-deck to
   the forecastle, being the uppermost bend, which finishes the
   upper works of the hull. [Written also {gunnel}.]

Source : WordNet®

gunwale
     n : wale at the top of the side of boat; topmost planking of a
         wooden vessel [syn: {gunnel}, {gun rest}]