-
A rare, dense, silvery-white metallic element with a very high melting point used for electrical contacts and with tungsten for high-temperature thermocouples. Atomic number 75; atomic weight 186.2; melting point 3,180°C; boiling point 5,627°C; specific gravity 21.02; valence 1, 2, 3, 4, 5, 6, 7. 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.