Meaning

noun a ductile grey metallic element of the lanthanide series; used in lighter flints; the most abundant of the rare-earth group

originFrom Ceres (“a famous asteroid”) + -ium. The element was discovered and named in 1803. It was named after the asteroid, which had been discovered recently (1801) and had been named after Ceres, the Roman goddess of agriculture. This was during an era when asteroids were culturally exciting things that humans were just beginning to understand properly in astronomical terms, and the era also…

Etymology from Wiktionary, CC BY-SA 3.0