Cu″pel (kū″pĕl), n. [LL. cupella cup (cf. L. cupella, small cask, dim. of cupa): cf. F. coupelle. See Cup, and cf. Coblet.] A shallow porous cup, used in refining precious metals, commonly made of bone ashes (phosphate of lime). [Written also coppel.]
Cupel dust, powder used in purifying metals.