Webster's Revised Unabridged Dictionary · 1913

Cupel

Cupel (kū"pel) , noun

[Late Latin cupella cup (compare Latin cupella, small cask, dim. of cupa): compare French coupelle. See Cup, and compare Coblet.]

A shallow porous cup, used in refining precious metals, commonly made of bone ashes (phosphate of lime).
Collocations (1)
Cupel dust , powder used in purifying metals.

Cupel (ku*pel") , transitive verb

To refine by means of a cupel.