-bēəm noun
( -s )
Etymology: New Latin, from Ytterby, Sweden, where gadolinite is found + New Latin -ium
: a metallic element of the rare-earth group that closely resembles yttrium and occurs with it and other related elements in several minerals (as xenotime and gadolinite) and that forms green salts in which it is bivalent and colorless salts in which it is trivalent — symbol Y b ; see element table