Definition of planchet in US English:

planchet

noun

  • A plain metal disk 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’.

Pronunciation

planchet

/ˈplan(t)SHət//ˈplæn(t)ʃət/