Redtop \Red"top`\ (-t?p`), n. (Bot.)
A kind of grass ({Agrostis vulgaris}) highly valued in the
United States for pasturage and hay for cattle; -- called
also {English grass}, and in some localities {herd's grass}.
See Illustration in Appendix. The tall redtop is {Triodia
seslerioides}.
[1913 Webster]