[dɪˈdɪmɪəm], (Noun)

Definitions:
- a mixture containing the rare earth elements praseodymium and neodymium, used to colour glass for optical filters. It was originally regarded as a single element


Phrases:

Origin:
mid 19th century: from Greek didumos ‘twin’ (because it was closely associated with lanthanum) + -ium (used as a suffix for new metals)