sole \sole\, n. f. sole, l. solea; -- so named from its flat
   shape. see sole of the foot. zool.
   a any one of several species of flatfishes of the genus
       solea and allied genera of the family soleidae,
       especially the common european species solea
       vulgaris, which is a valuable food fish.
   b any one of several american flounders somewhat resembling
       the true sole in form or quality, as the california sole
       lepidopsetta bilineata, the long-finned sole
       glyptocephalus zachirus, and other species.
       1913 webster

   lemon, or french, sole zool., a european species of
      sole solea pegusa.

   smooth sole zool., the megrim.
      1913 webster
see also:
sole solea soleidae solea vulgaris lepidopsetta bilineata glyptocephalus zachirus 
lemon french sole solea pegusa smooth sole