Chem. [mod.L., from the last two syllables of the name of Ytterby in Sweden: cf. ERBIUM.] One of the rare metallic elements found (together with yttrium and erbium) in gadolinite and other minerals. So Terbia [after ERBIA], the earth or oxide of terbium.
1843. Mosander in L., E., & D. Philos. Mag., XXIII. 251. What chemists have hitherto considered as yttria, does not consist of one oxide only, but is … to be regarded as a mixture of at least three…. If the name of yttria be reserved for the strongest of these bases, and the next in order receive the name of oxide of terbium, while the weakest be called oxide of erbium, we find [etc.].
1907. Roscoe & Schorlemmer, Chemistry, II. 783. Terbium Tb = 158 (H = 1)…. The existence of the earth originally called erbia by Mosander was denied by Berlin (1860), and by Bahr and Bunsen (1866), but was confirmed by Delafontaine (1878), and by Marignac. It then received the name of terbia…. Pure terbium compounds were first obtained by Urbain [1905, 1906].
