Feature changing space and time (6)
I believe the answer is:
aspect
'feature' is the definition.
(aspect is a kind of feature)
'changing space and time' is the wordplay.
'changing' is an anagram indicator.
'and' means one lot of letters go next to another.
'time' becomes 't'.
'space' is an anagram of 'aspec'.
'aspec'+'t'='ASPECT'
(Other definitions for aspect that I've seen before include "Distinct part or element" , "Vista,panorama" , "Feature; appearance" , "particular view" , "View or facet" .)