A soft, silvery, highly reactive metallic element that is used as a heat transfer medium, in thermonuclear weapons, and in various alloys, ceramics, and optical forms of glass. Atomic number 3; atomic weight 6.941; melting point 179°C; boiling point 1,317°C; specific gravity 0.534; valence 1. See Table at element.
Any of several salts of lithium, especially lithium carbonate.
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.