The Collaborative International Dictionary
Ray grass
Ray grass \Ray" grass`\ (r[=a]" gr[.a]s`). [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 grass or Italian rye grass. See Darnel, and Grass.
Wiktionary
ray grass
n. A perennial European grass ((taxlink Lolium perenne species)); rye grass; red darnel.