perhaps the word, res. which means: Matter, affair, thing, circumstance
res
law
Lex.
law
lex
law
law
A three-letter word that means "rules" is law.Some example sentences are:Police officers enforce the law.The law states that you must not steal.
that is the Law of Conservation of Matter.
There is the law of conservation of mass, and the law of conservation of energy. All three state: (Mass/Matter/Energy) cannot be created or destroyed, simply transferred.
law
Law
law