piston: [18] The Latin verb pinsere meant ‘beat, pound’. Its past participial stem pist- formed the basis for the noun pistillum ‘grinding stick, pestle’ (from which English gets pistil ‘female flower part’ [18], an allusion to its shape). This passed into Italian as pestello, from which English gets pestle [14]. From the Italian stem pest- was formed pestone ‘rammer’, whose variant pistone gave French piston – whence English piston. => pestle, pistil
