Emily Dickinson Lexicon

COUN'TER-POISE, n. [Fr. contrepoids; It. contrappeso; Sp. contrapeso.]

1. Equal weight acting in opposition to something; equiponderance; a weight sufficient to balance another in the opposite scale; equal balance. – Milton.
2. Equal power or force acting in opposition; a force sufficient to balance another force; equipollence. The second nobles are a counterpoise to the higher nobility. – Bacon.
3. In the manege, a position of the rider in which his body is duly balanced in his seat, not inclined more to one side than the other. – Encyc.