from The American Heritage® Dictionary of the English Language, 4th Edition
- n. A radioactive rare-earth element prepared by fission of uranium or by neutron bombardment of neodymium, having 14 isotopes with mass numbers ranging from 141 to 154 and used as a source of beta rays. Atomic number 61; melting point 1,168°C; boiling point 2,460°C; valence 3. See Table at element.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. a metallic chemical element (symbol Pm) with an atomic number of 61.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- n. a soft silvery metallic element of the rare earth group having no stable isotope; was discovered in radioactive form as a fission product of uranium
From Prometheus.(American Heritage® Dictionary of the English Language, Fourth Edition)
1945. From the name of the Greek god Prometheus, who stole the fire from Mount Olympus and brought it down to mankind. (Wiktionary)