counterpoise

noun

1. A weight sufficient to balance another, for example in the opposite end of scales; an equal weight.
2. An effect of equal power or force acting in opposition; a force sufficient to balance another force or influence

   “This necessary counterpoise, the affectionate and simple-minded will readily conceive, would arise to Louisa from the absence of those "dear familiar faces" which had hitherto constituted her world.”

3. The relation of two weights or forces which balance each other; equilibrium

verb

1. To act against with equal weight; to equal in weight; to balance the weight of; to counterbalance.

   “Weights, counterpoising one another.”

2. To act against with equal power; to balance.

   “So many freeholders of English […]will be able to beard, and to counterpoise the rest.”