British Dictionary definitions for relative permittivity
the ratio of the permittivity of a substance to that of free space εrAlso called dielectric constant
noun (pl) -ties
a measure of the response of a substance to an electric field, expressed as the ratio of its electric displacement to the applied field strength; measured in farads per metre ε See also relative permittivity, electric constant
relative permittivity The ratio of the magnetic permittivity of a substance to the permittivity of a vacuum.
(pûr'mĭ-tĭv'ĭ-tē) A measure of the ability of a material to resist the formation of an electric field within it, equal to the ratio between the electric flux density and the electric field strength generated by an electric charge in the material.