[di.dym.i.um] n [NL, fr. Gk didymos twin, fr. dyo two--more at two] (1842): a mixture of rare-earth elements made up chiefly of neodymium and praseodymium and used esp. for coloring glass for optical filters
DIDYMIUM
Meaning of DIDYMIUM in English
Merriam-Webster English vocab. Английский словарь Merriam Webster. 2012