Constant

1. Consistent; logical.
2. A quantity that does not change its value; -- used in countradistinction to variable.
3. Firm; solid; fixed; immovable; -- opposed to fluid.
4. Not liable, or given, to change; permanent; regular; continuous; continually recurring; steadfast; faithful; not fickle.
5. Remaining unchanged or invariable, as a quantity, force, law, etc.
6. That which is not subject to change; that which is invariable.