What is "stable equilibrium"

Stable \Sta"ble\ (st[=a]"b'l), a. [OF. estable, F. stable, fr. L. stabilis, fr. stare to stand. See Stand, v. i. and cf. Establish.]

1. Firmly established; not easily moved, shaken, or overthrown; fixed; as, a stable government.

   In this region of chance, . . . where nothing is stable.
   --Rogers.

2. Steady in purpose; constant; firm in resolution; not easily diverted from a purpose; not fickle or wavering; as, a man of stable character.

   And to her husband ever meek and stable.
   --Chaucer.

3. Durable; not subject to overthrow or change; firm; as, a stable foundation; a stable position.

4. (Physics) So placed as to resist forces tending to cause motion; of such structure as to resist distortion or molecular or chemical disturbance; -- said of any body or substance.

   Stable equilibrium (Mech.), the kind of equilibrium of a body so placed that if disturbed it returns to its former position, as in the case when the center of gravity is below the point or axis of support; -- opposed to unstable equilibrium, in which the body if disturbed does not tend to return to its former position, but to move farther away from it, as in the case of a body supported at a point below the center of gravity. Cf. Neutral equilibrium, under Neutral.

   Syn: Fixed; steady; constant; abiding; strong; durable; firm.

Stable equilibrium can refer to:

• Homeostasis, a state of equilibrium used to describe organisms
• Mechanical equilibrium, a state in which all particles in a system are at rest, and total force on each particle is permanently zero
• Balance of nature, a theory in ecological science
• Stability theory, a theory in mathematics
• Mertens-stable equilibrium in game theory
• Stochastically stable equilibrium in game theory