adj. & n.
--adj.
1. (often foll. by to) equal in value, amount, importance, etc.
2 corresponding.
3 (of words) having the same meaning.
4 having the same result.
5 Chem. (of a substance) equal in combining or displacing capacity.
--n.
1. an equivalent thing, amount, word, etc.
2 (in full equivalent weight) Chem. the weight of a substance that can combine with or displace one gram of hydrogen or eight grams of oxygen.
Derivatives:
equivalence n. equivalency n. equivalently adv.
Etymology: ME f. OF f. LL aequivalere (as EQUI-, valere be worth)