Lucius is a masculine given name which began use as Lucius (Latin [ˈluː.ki.us]; Etruscan: Luvcie), abbreviated L., one of the small group of common Latin forenames (praenomina) found in the culture of ancient Rome. Lucius probably derives from Latin word lux (gen. lucis), meaning "light" (<PIE *leuk-, "brightness"), related to the Latin verb lucere ("to shine") and cognate to the name Lucas. Another proposed etymology is derivation from Etruscan Lauchum (or Lauchme) meaning "king", which was more directly transferred into Latin as Lucumo. . Lucia and Lucy are feminine forms of the name.
https://en.wikipedia.org/wiki/Lucius