valence medical definition

or va·len·cy

1. The combining capacity of an atom or radical that is determined by the number of electrons that it will lose, add, or share when it reacts with other atoms.
2. A positive or negative integer used to represent this capacity.
3. The number of components of an antigen molecule to which an antibody molecule can bind.
4. The attraction or aversion that an individual feels toward a specific object or event.