Heaps constructed on stage (5)
I believe the answer is:
phase
'stage' is the definition.
('phase' can be a synonym of 'stage')
'heaps constructed' is the wordplay.
'constructed' indicates an anagram.
'heaps' with letters rearranged gives 'PHASE'.
'on' is the link.
(Other definitions for phase that I've seen before include "Period or stage in a process of change" , "stage in process of development" , "Distinct stage" , "A particular point in the time of a cycle" , "Truman -, US novelist" .)