n. - 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.
n. - A hollow place at the bottom of a furnace, to receive the melted metal.
n. - A test of the most decisive kind; a severe trial; as, the crucible of affliction.