Related formster·bic, adjective
Examples from the Web for terbium
Erbium, a rare metal found along with yttrium, terbium, and other rare elements in some rare minerals.The New Gresham Encyclopedia|Various
(c.) Yttria (YO) occurs only in a few rare minerals, and usually in company with terbium and erbium.
Terbium, ter′bi-um, n. a rare metal found in certain yttrium minerals.