φανόν

From LSJ

νέῳ δὲ σιγᾶν μᾶλλον ἢ λαλεῖν πρέπει → it's fitting for a young man to keep silence rather than to speak (Menander)

Source

Russian (Dvoretsky)

φᾱνόν: τό яркость, свет Xen., Plat.