valence

The combining capacity of an atom, functional group, or radical determined by the number of atoms of hydrogen with which it will unite, or the number of electrons that it will gain, lose, or share when it combines with other atoms, etc.

The number of binding sites of a molecule, such as an antibody or antigen.

The number of arguments that a verb can have, including its subject, ranging from zero to three or, less commonly, four.

A one-dimensional value assigned by a person to an object, situation, or state, that can usually be positive (causing a feeling of attraction) or negative (repulsion).

The value which a person places on something.

For a correspondence T on a curve: a number k such that the divisors T(P)+kP are all linearly equivalent.