The roots of the word helicopter are not heli and copter but helico and pter, from the Greek “helix” (spiral) and “pteron” (wing).

G.L.M. de Ponton’s 1861 British patent says, “The required ascensional motion is given to my aerostatical apparatus (which I intend denominating aeronef or helicoptere,) by means of two or more superposed horizontal helixes combined together.”