from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. A heavy isotope of the simplest alkali metal, (symbol Li) with an atomic number of 3 and containing 8 neutrons. Metalithium is an artificial isotope produced by bombarding Lithium 7 with neutrons. It is radioactive, with a half-life of 0.84 seconds.
meta- + lithium (Wiktionary)