noun
: an arbitrary standard of prismatic deflection equal to that of a prism that deflects a beam of light one centimeter on a plane placed at a distance of one meter
noun
: an arbitrary standard of prismatic deflection equal to that of a prism that deflects a beam of light one centimeter on a plane placed at a distance of one meter
Webster's New International English Dictionary. Новый международный словарь английского языка Webster. 2012