ビリアル定てい理りMeanings1nounvirial theoremphysicsA theorem in physics relating the average kinetic energy of a system to its average potential energy.ビリアル定てい理りは、星ほしの内ない部ぶ構こう造ぞうを調しらべるのに使つかわれる。The virial theorem is used to study the internal structure of stars.