n. [ LL. crucibulum a hanging lamp, an earthen pot for melting metals (cf. OF. croisel, creuseul, sort of lamp, crucible, F. creuset crucible), prob. of German origin; cf. OHG. krūsul, LG. krüsel, hanging lamp, kroos, kruus, mug, jug, jar, D. kroes cup, crucible, Dan. kruus, Sw. krus, E. cruse. It was confused with derivatives of L. crux cross (cf. Crosslet), and crucibles were said to have been marked with a cross, to prevent the devil from marring the chemical operation. See Cruse, and cf. Cresset. ] 1. A vessel or melting pot, composed of some very refractory substance, as clay, graphite, platinum, and used for melting and calcining substances which require a strong degree of heat, as metals, ores, etc. [ 1913 Webster ]

2. A hollow place at the bottom of a furnace, to receive the melted metal. [ 1913 Webster ]

3. A test of the most decisive kind; a severe trial; as, the crucible of affliction. [ 1913 Webster ]

Hessian crucible (Chem.), a cheap, brittle, and fragile, but very refractory crucible, composed of the finest fire clay and sand, and commonly used for a single heating; -- named from the place of manufacture. [ 1913 Webster ]

. Cast steel made by fusing in crucibles crude or scrap steel, wrought iron, and other ingredients and fluxes. [ Webster 1913 Suppl. ]