“Both portions viewed as units, vastly differing in volume, perfectly equal in mass, are in a constant state of equilibrium.”
“I sighed a long breath, trying to regain my equilibrium despite the emotional and psychic assault.”
“I was able to stop all medication and to maintain my equilibrium despite further recent experiences of abandonment, betrayal and rejection.”
equilibrator
(rare) A device that maintains equilibrium or balance, especially a part of a heavy gun (e.g. an artillery piece or a tank gun) which balances the barrel and other parts so as to enable the gun to be elevated easily.