A trivalent metallic element of the rare earth group, occurs with yttrium
English: erbium, Er, atomic number 68
erbiumEnglish
Er, atomic number 68, erbium, fergusonite
Rare
#112,682 of the corpus · 0.1 per million words · 377 occurrences
Noun
A dark mineral consisting of oxides of yttrium and erbium and tantalum and other minerals
English: fergusonite
Less certain link between this word and this sense.