platenPronunciation: /ˈplat(ə)n/Definition of platen noun 1the plate in a small letterpress printing press which presses the paper against the type. 2the cylindrical roller in a typewriter against which the paper is held. Origin: late 16th century: from French platine 'flat piece' from plat 'flat'platen in other Oxford dictionaries Definition of platen in the US English dictionary