rhombus levis

from The Collaborative International Dictionary of English v.0.48

Brill \Brill\, n. [Cf. Corn. brilli mackerel, fr. brith
   streaked, speckled.] (Zool.)
   A fish allied to the turbot ({Rhombus levis}), much esteemed
   in England for food; -- called also {bret}, {pearl}, {prill}.
   See {Bret}.
   [1913 Webster]