'film' in its modern sense (for photographic material and then motion pictures) developed in English in the late 19th century from the earlier sense 'a thin layer or coating'.

'film' changed from Old English 'filmen' (meaning 'membrane, skin') through Middle English, where it meant 'thin skin or membrane' and later 'a thin layer', then was applied to 'photographic film' and finally to 'motion picture' (modern 'film').

Initially, it meant 'membrane' or 'skin'; over time it shifted to 'a thin layer or coating', then to 'photographic medium' and ultimately to 'motion picture'.