term:

Supremacy Clause

supremacy clause n

often cap S&C
: a clause in Article VI of the U.S. Constitution that declares the constitution, laws, and treaties of the federal government to be the supreme law of the land to which judges in every state are bound regardless of state law to the contrary

Source: Merriam-Webster's Dictionary of Law ©1996. Merriam-Webster, Incorporated. Published under license with Merriam-Webster, Incorporated.