Grassy plain (7)
I believe the answer is:
prairie
'grassy plain' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for prairie that I've seen before include "Great grassland area" , "Large tract of grassland in N America" , "Wide grassy plain" , "Large open area of grassland in the US" , "Cowboy song: ` `Bury me not on the lone .......' '" .)