noun
: a bluish glass often colored with cobalt that is used with incandescent lamps to absorb the excess radiations in the red part of the spectrum and thus give the effect of daylight
noun
: a bluish glass often colored with cobalt that is used with incandescent lamps to absorb the excess radiations in the red part of the spectrum and thus give the effect of daylight
Webster's New International English Dictionary. Новый международный словарь английского языка Webster. 2012