What is Absolute Law?

Legal Definition
Any law that follows the rules of nature and a law that is changeless. It may be an absolute law but in an abstract sense and not always exercised in actuality. See law of nature.
Legal Definition
The true and proper law of nature, immutable in the abstract or in principle, in theory, but not in application; for very often the object, the reason, situation, and other circumstances, may vary its exercise and obligation. 1 Steph. Comm. 21 et seq.
-- Black's Law Dictionary