DuckCorp Dico

Found one definition

1.                 From The Collaborative International Dictionary of English v.0.48:
                   
   
   
                   
                     
   Sun \Sun\, v. t. [imp. & p. p. Sunned; p. pr. & vb. n.
      Sunning.]
      To expose to the sun's rays; to warm or dry in the sun; as,
      to sun cloth; to sun grain.
      [1913 Webster]
            Then to sun thyself in open air.         --Dryden.
      [1913 Webster]