Clump of turf (3)
I believe the answer is:
sod
'clump of turf' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for sod that I've seen before include "Surface layer of ground with grass roots" , "Lump of earth" , "A lulmp of turf" , "Piece of grassy soil" , "A piece of sward." .)