liv·er·mo·ri·um 
(lĭv′ər-môrē-əm)
(lĭv′ər-môrē-əm)n. Symbol Lv
An artificially produced radioactive element with atomic number 116 that has only been produced in trace amounts and has five observed isotopes with mass numbers ranging from 289 to 293. Its most stable isotope has a half-life of about 53 milliseconds. See Periodic Table.
[After the Lawrence Livermore National Laboratory located in Livermore, California, which collaborated in its discovery.]