Английский разговорный словарь (основной) - fluorescence

fluəˈresns n. 1 the visible or invisible radiation produced from certain substances as a result of incident radiation of a shorter wavelength as X-rays, ultraviolet light, etc. 2 the property of absorbing light of short (invisible) wavelength and emitting light of longer (visible) wavelength. [FLUORSPAR (which fluoresces) after opalescence]