a radioactive, metallic chemical element, the last member of the actinide series: originally produced by bombarding californium with boron nuclei: symbol, Lr; at. no., 103
See lawrencium in American Heritage Dictionary 4
(lô-rĕnˈsē-əm, lō-)
noun Symbol Lr
A short-lived, radioactive synthetic transuranic element produced from californium and whose most stable isotope has a mass number of 262 with a half-life of 3.6 hours; atomic number 103. See Table at element.