Enclosed area: three feet (4)
I believe the answer is:
yard
I believe this is a double definition.
'enclosed area' is the first definition.
(I've seen this before)
'three feet' is the second definition.
(I've seen this in another clue)
(Other definitions for yard that I've seen before include "Court" , "Police" , "Measure - enclosed paved area" , "short distance" , "3ft" .)