Definition of regulus
1 capitalized : a first-magnitude star in the constellation Leo
2 [Medieval Latin, metallic antimony, from Latin] : the more or less impure mass of metal formed beneath the slag in smelting and reducing ores
Origin of regulus
New Latin, from Latin, petty king, from reg-, rex king — more at royal
First Known Use: 1559
Learn More about regulus
Britannica.com: Encyclopedia article about "regulus"
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