Measure; enclosure (4)
I believe the answer is:
yard
I believe this clue is a double definition.
'measure' is the first definition.
(yard is a kind of measure)
'enclosure' is the second definition.
(I know that yard is a type of enclosure)
(Other definitions for yard that I've seen before include "36 inches" , "A little under a metre" , "area behind the house" , "several feet" , "Police" .)