A scientific law is a repeated experimental observation that describes some aspect of the universe
A scientific theory is a well supported explanation of some natural phenomenon.
What is the difference between a scientific theory and a scientific law?
One is a maybe. The other is fact.
There are no "laws" in science, the highest category in science is a "theory". In science the term "law" and "theory" is the same.
Dictionary.com
Theory:
a coherent group of tested general propositions,commonly regarded as correct, that can be used as principles of explanation and prediction for a class of phenomena:
Einstein's theory of relativity.
Synonyms: principle, law, doctrine.