Condition or period of equilibrium (6)

I believe the answer is:

stasis

(Other definitions for stasis that I've seen before include "Inactive state" , "Condition of arrested progress" , "State of immobility or inactivity" , "State in which blood-flow is stopped" , "Total lack of movement" .)

I've seen this clue in The Sunday Times and The Times.

Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.