Measure enclosed space (4)
I believe the answer is:
yard
I believe this is a double definition.
'measure' is the first definition.
(yard is a kind of measure)
'enclosed space' is the second definition.
(I've seen this before)
(Other definitions for yard that I've seen before include "Imperial unit of length" , "Court" , "short distance" , "Space outside" , "Enclosed area by building - old measure" .)