planchet
/ˈplan(t)ʃɪt
/noun
A plain metal disc from which a coin is made.The leachate was separated from the solids by centrifugation, and the dissolved polonium isotopes in the liquid were plated spontaneously onto a silver planchet....
- The most basic type of planchet error is when the wrong planchet is fed into a press.
Origin
Early 17th century: diminutive of earlier planch 'slab of metal', from Old French planche 'plank, slab'.