Relating to space (7)
I believe the answer is:
spatial
'relating to space' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for spatial that I've seen before include "describing area?" , "Of arrangements in three dimensions" , "Of room; alas tip (anag.)" , "Space-related (T, not C)" , "Relating to space" .)