Today's Word of the Day means...
photoluminescent pho·to·lu·mi·nes·cent (fō'tō-lōō'mə-něs'ənt)
Having the ability to become luminescent upon exposure to visible light.
emission of light from a substance as a result of absorption of electromagnetic radiation; such a substance is called a phosphor (q.v.), and the emitted light usually has a longer wavelength than the incident radiation.