Space at edge of page (6)
I believe the answer is:
margin
'space at edge of page' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for margin that I've seen before include "Bound" , "Blank space that surrounds the text on a page" , "Periphery" , "Space at edge of page" , "Boundary line or the area" .)