Source : Webster's Revised Unabridged Dictionary (1913)

Ray grass \Ray" grass`\, [Etymol. of ray is uncertain.] (Bot.)
   A perennial European grass ({Lolium perenne}); -- called also
   {rye grass}, and {red darnel}. See {Darnel}, and {Grass}.

   {Italian} {ray, or rye}, {grass}. See {Darnel}, and {Grass}.