What is "coercitive force"

Coercive \Co*er"cive\, a. Serving or intended to coerce; having power to constrain. -- Co*er"cive*ly, adv. -- Co*er"cive*ness, n.

Coercive power can only influence us to outward practice.
--Bp. Warburton.

Coercive force or Coercitive force (Magnetism), the power or force which in iron or steel produces a slowness or difficulty in imparting magnetism to it, and also interposes an obstacle to the return of a bar to its natural state when active magnetism has ceased. It plainly depends on the molecular constitution of the metal.
--Nichol.

The power of resisting magnetization or demagnization is sometimes called coercive force.
--S. Thompson.