noun
equivalence principle
In physics, the principle that gravitational and inertial mass are equivalent; foundational to general relativity.
アインシュタインの等価原理は一般相対性理論の基礎となっている。
Einstein's equivalence principle is the foundation of general relativity.
Compound of 等価 (tōka, 'equivalence') and 原理 (genri, 'principle').