noun
dielectric constant; relative permittivity
Technical term in physics and electrical engineering. 'Specific inductive capacity' is an older synonym.
この材料の比誘電率は約4.5です。
The dielectric constant of this material is about 4.5.
Compound of 比 (ratio) + 誘電 (dielectric) + 率 (rate). The term is a direct technical translation of 'relative permittivity'.