Standard sort of paving stone (4)
I believe the answer is:
flag
This clue is a double definition.
'standard' is the first definition.
(standard is a type of flag)
'sort of paving stone' is the second definition.
(Other definitions for flag that I've seen before include "Draw attention to" , "what Amundsen planted" , "Iris -- become weary" , "Get weary" , "Droop; iris" .)