-ˈdimēəm noun
( -s )
Etymology: New Latin, alteration of praseodidymium
: a yellowish white trivalent metallic element of the rare-earth group that occurs usually with cerium, lanthanum, and neodymium, that forms green salts, and that is used chiefly in the form of its salts in coloring glass greenish yellow — symbol Pr ; see didymium; element table