noun
: a smooth plate that establishes the film plane in a motion-picture camera or projector and that has a rectangular opening defining the margins of the picture area as recorded or projected
noun
: a smooth plate that establishes the film plane in a motion-picture camera or projector and that has a rectangular opening defining the margins of the picture area as recorded or projected
Webster's New International English Dictionary. Новый международный словарь английского языка Webster. 2012