Period of equilibrium (6)
I believe the answer is:
stasis
'period of equilibrium' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for stasis that I've seen before include "Period of equilibrium" , "State in which blood-flow is stopped" , "Abnormal state in which the flow of blood is stopped" , "Inactive state" , "Condition of arrested progress" .)