The Collaborative International Dictionary of English v.0.48:

Ridge \Ridge\, v. t. [imp. & p. p. Ridged; p. pr. & vb. n.
   Ridging.]
   1. To form a ridge of; to furnish with a ridge or ridges; to
      make into a ridge or ridges.
      [1913 Webster]

            Bristles ranged like those that ridge the back
            Of chafed wild boars.                 --Milton.
      [1913 Webster]

   2. To form into ridges with the plow, as land.
      [1913 Webster]

   3. To wrinkle. "With a forehead ridged." --Cowper.
      [1913 Webster]

WordNet (r) 3.0 (2006):

ridged
    adj 1: having a ridge or shaped like a ridge or suggesting the
           keel of a ship; "a carinate sepal" [syn: ridged,
           carinate, carinated, keeled]