Английский Этимологический словарь - platform

- 1550, "plan of action, scheme, design," from M.Fr. plate-forme, lit. "flat form," from O.Fr. plate "flat" + forme "form." The literal sense of "raised, level surface" is first recorded 1560. Political meaning, "statement of party policies," is from 1803, from "set of rules governing church doctrine" (first attested 1648). Railroad station sense is from 1838.