Range, extent (4)
I believe the answer is:
span
I believe this clue is a double definition.
'range' is the first definition.
(I've seen this before)
'extent' is the second definition.
(I've seen this in another clue)
(Other definitions for span that I've seen before include "Distance between two points in time or place" , "Bridge or range" , "Ox team; bridge" , "A bridge or measure of width" , "Team of two matched oxen" .)