Source : Webster's Revised Unabridged Dictionary (1913)

Heel \Heel\ (h[=e]l), v. i. [OE. helden to lean, incline, AS.
   heldan, hyldan; akin to Icel. halla, Dan. helde, Sw. h["a]lla
   to tilt, pour, and perh. to E. hill.] (Naut.)
   To lean or tip to one side, as a ship; as, the ship heels
   aport; the boat heeled over when the squall struck it.

   {Heeling error} (Naut.), a deviation of the compass caused by
      the heeling of an iron vessel to one side or the other.