Ewe's milieu (3)
I believe the answer is:
lea
'ewe's milieu' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for lea that I've seen before include "River of east London" , "Field" , "''The lowing herd winds slowly o'er the ... '' (Gray)" , "Open country" , "Land growing grass" .)