Source : Webster's Revised Unabridged Dictionary (1913)

Keel \Keel\, v. i. [imp. & p. p. {Keeled}; p. pr. & vb. n.
   {Keeling}.]
   1. To traverse with a keel; to navigate.

   2. To turn up the keel; to show the bottom.

   {To keel over}, to upset; to capsize. [Colloq.]