Equilibrium (?), n.; pl. E. Equilibriums (#), L. Equilibria (#). [L. aequilibrium, fr. aequilibris in equilibrium, level; aequus equal + libra balance. See Equal, and Librate.] 1. Equality of weight or force; an equipoise or a state of rest produced by the mutual counteraction of two or more forces.
[1913 Webster]

2. A level position; a just poise or balance in respect to an object, so that it remains firm; equipoise; as, to preserve the equilibrium of the body.
[1913 Webster]

Health consists in the equilibrium between those two powers. Arbuthnot.
[1913 Webster]

3. A balancing of the mind between motives or reasons, with consequent indecision and doubt.
[1913 Webster]

Equilibrium valve (Steam Engine), a balanced valve. See under Valve.
[1913 Webster]