planchet (n.)youdaoicibaDictYouDict[planchet 词源字典]
"metal disk out of which a coin is made," 1610s, from French planchette, literally "a small board," diminutive of Old French planche (12c.), from Latin planca "board, slab, plank" (see plank). The planchette used in automatism and on Ouija boards is a re-borrowing of the French word, 1860.[planchet etymology, planchet origin, 英语词源]