equivalent-n; 2 Senses

Sense Number 1: A person or thing equal to another in value or significane.

Commentary: EQUIVALENT[+person][+thing]

She is the equivalent of any man on the team.
The two kinds of problems are equivalents of one another.
Send two dollars or the equivalent in stamps.

WordNet 3.0 Sense Numbers: 1

Sense Number 2: (science) The atomic weight of an element that has the same combining capacity as a given weight of another element.

NOTE: Use only for this specific science meaning. EQUIVALENT[+computer_science]

The equivalent is 8 for oxygen.
We must find the equivalent in hydrogen.

WordNet 3.0 Sense Numbers: 2