Regulus /(-l?s)/

Reg·u·lus

Regulus

n.

pl. Reguluses, Reguli ((-z))

  1. A petty king; a ruler of little power or consequence.
  2. The button, globule, or mass of metal, in a more or less impure state, which forms in the bottom of the crucible in smelting and reduction of ores. (Chem. & Metal.)
  3. A star of the first magnitude in the constellation Leo; -- called also the Lion's Heart. (Astron.)