Emily Dickinson Lexicon

E-QUIV'A-LENT, n.

1. That which is equal in value, weight, dignity, or force, with something else. The debtor can not pay his creditor in money, but he will pay him an equivalent. Damages in money can not be an equivalent for the loss of a limb.
2. In chimistry, equivalent is the proportion expressing the weight or quantity of any substance which combines with another substance to form a definite compound. It is often called chimical equivalent, or combining proportion.