What is another word for rest mass?
Pronunciation: [ɹˈɛst mˈas] (IPA) 
Rest mass refers to the intrinsic mass of an object when it is at rest. The term is mainly used in physics and is commonly known as the mass of an object in its rest frame. Some synonyms for rest mass that are often used in scientific literature include invariant mass, rest energy, and proper mass. Each of these synonyms describes the same concept: the mass of an object when it is not in motion relative to the observer. Other synonyms for rest mass that may be used less commonly include intrinsic mass, static mass, and zero-motion mass. Regardless of the synonym used, the concept of rest mass remains a fundamental concept in physics.
