Counterpoise

Etymology
From countrepeis:, contrepeser:, later assimilated to poise:.

Noun

 * 1) A weight sufficient to balance another, as in the opposite scale of a balance; an equal weight.
 * 2) An equal power or force acting in opposition; a force sufficient to balance another force.
 * 3) The relation of two weights or forces which balance each other; equilibrium; equiponderance.

Verb

 * 1) To act against with equal weight; to equal in weight; to balance the weight of; to counterbalance.
 * 2) To act against with equal power; to balance.