bivalence

noun
  1. the quality or state of having two values, meanings, or interpretations
  2. Usage: formal; often used in logic, philosophy, and linguistics
  3. in logic, the principle that every proposition is either true or false, with no third option
  4. Usage: technical; philosophy and logic
  5. in chemistry, the capacity of an atom or radical to form two bonds
  6. Usage: technical; chemistry

Examples