crucible

Etymology

From Latin crucibulum (“night-lamp, metallurgic melting-pot”), apparently a derivative of crux (“cross”), perhaps by analogy to thūribulum (“censer”) and suffix -bulum, or from crucio (“to torment”).

noun

1. (chemistry) A cup-shaped piece of laboratory equipment used to contain chemical compounds when heating them to very high temperatures.
   In one corner of the closet was a very small furnace, with a glowing fire in it, and on the fire a kind of duplicate crucible—two crucibles connected by a tube. One of these crucibles was nearly full of lead in a state of fusion, but not reaching up to the aperture of the tube, which was close to the brim. 1850, Edgar Allan Poe, “Von Kempelen and His Discovery”, in The Works of the Late Edgar Allan Poe
2. A heat-resistant container in which metals are melted, usually at temperatures above 500°C, commonly made of graphite with clay as a binder.
3. The bottom and hottest part of a blast furnace; the hearth.
4. (figurative) A very difficult and trying experience, that acts as a refining or hardening process.
   Coordinate term: trial by fire
   We should give our support to the liberation of the captive nations of the world and deliver our compatriots from their crucible of suffering. In other words, we should take up the difficult task of reshaping the world’s destiny by destroying the tyrannical Communist rule now afflicting the earth and by delivering humankind from the Red holocaust. July 22, 1973 [July 17, 1973], Kai-shek Chiang, “President Chiang Kai-shek's message to the mass rally supporting Captive Nations Week”, in Free China Weekly, volume XIV, number 28, Taipei, →ISSN, →OCLC, page 1
   Some of our ancestors faced trials that we will never know—the snows of Valley Forge; the crucible of a bitter, bloody civil war; and the incredible hardships endured in taming a savage wilderness. 1982-07-03, Ronald Reagan, Presidential Radio Address