From BiblePortal Wikipedia

Webster's Dictionary [1]

(1): (v. t.) Consistent; logical.

(2): (n.) A quantity that does not change its value; - used in countradistinction to variable.

(3): (v. t.) Remaining unchanged or invariable, as a quantity, force, law, etc.

(4): (n.) A number expressing some property or condition of a substance or of an instrument of precision; as, the dielectric constant of quartz; the collimation constant of a transit instrument.

(5): (n.) A number whose value, when ascertained (as by observation) and substituted in a general mathematical formula expressing an astronomical law, completely determines that law and enables predictions to be made of its effect in particular cases.

(6): (n.) That which is not subject to change; that which is invariable.

(7): (v. t.) Firm; solid; fixed; immovable; - opposed to fluid.

(8): (v. t.) Not liable, or given, to change; permanent; regular; continuous; continually recurring; steadfast; faithful; not fickle.

King James Dictionary [2]

Constant, a. L.

1. Fixed firm opposed to fluid.

To turn two fluid liquors into a constant body.

In this sense, not used.

2. Fixed not varied unchanged permanent immutable.

The worlds a scene of changes, and to be constant, in nature were inconstancy.

3. Fixed or firm in mind, purpose, affection or principle unshaken unmoved as a constant friend or lover. 4. Certain steady firmly adherent with to as a man constant to his purpose, or to his duties.