PHOT Meaning of PHOT in English /fot, foht/ , n. Optics.a unit of illumination, equal to 1 lumen per square centimeter. Abbr.: ph [ 1915-20; phot-, s. of phôs (contr. of pháos ) light ] Random House Webster's Unabridged English dictionary. Полный английский словарь Вебстер - Random House . 2012