Source : Webster's Revised Unabridged Dictionary (1913)

Sea anchor \Sea" an"chor\ (Naut.)
   See {Drag sail}, under 4th {Drag}.

Source : WordNet®

sea anchor
     n : restraint consisting of a canvas covered frame that floats
         behind a vessel; prevents drifting or maintains the
         heading into a wind [syn: {drogue}]