Definition of "terbium" [ter•bi•um]

• A soft, silvery-gray metallic rare-earth element, used in x-ray and color television tubes. Atomic number 65; atomic weight 158.925; melting point 1,356°C; boiling point 3,123°C; specific gravity 8.229; valence 3, 4. See Table at element. (noun)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "Indeed, some international prices haven't fallen at all, in particular those that are known as heavy rare earths, like terbium, which is used in advanced lasers and optics."
• "The rare-earths blasted out of rocks here feed more than 77 per cent of global demand for elements such as terbium, which power low-energy lightbulbs; neodymium, which powers wind turbines; and lanthanum, which powers the batteries of hybrid cars such as the Toyota Prius."
• "The insides of energy-efficient compact fluorescent light bulbs are coated with tiny amounts of two such elements, terbium and europium."