equilibrium

(noun) a stable situation in which forces cancel one another.

(noun) a chemical reaction and its reverse proceed at equal rates. Synonyms: chemical equilibrium.

(noun) equality of distribution. Synonyms: balance, equipoise, counterbalance.

(noun) a sensory system located in structures of the inner ear that registers the orientation of the head. Synonyms: labyrinthine sense, vestibular sense, sense of balance, sense of equilibrium.