Astronomy. Regulus, a first magnitude star in the constellation Leo.
Metallurgy.
the metallic mass that forms beneath the slag at the bottom of the crucible or furnace in smelting ores.
an impure intermediate product obtained in smelting ores.
First recorded in 1550–60; from Latin rēgulus literally, “little king” (diminutive of rēx ); in early chemistry, “antimony,” so called because it readily combines with gold (the king of metals); see -ule
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Thus the silver, as in the last process, is converted into a sulphide, and is absorbed in the regulus, while the metallic antimony alloys with the gold and settles to the bottom of the pot.
From De Re Metallica, Translated from the First Latin Edition of 1556 by Agricola, Georgius
For clarity we introduced the term "regulus" for the Latin mistura.
From De Re Metallica, Translated from the First Latin Edition of 1556 by Agricola, Georgius
To separate the copper from the silver we require five hundred librae of lead, more or less, with which the regulus is melted in the second furnace.
From De Re Metallica, Translated from the First Latin Edition of 1556 by Agricola, Georgius
A chemical compound so called from its power of dissolving gold. regulus of cobalt: early chemical term referring to the metallic mass of an ore.
From The Short-story by Atkinson, William Patterson
It is difficult to see the object of preserving the antimony with such a sulphurizing "addition," unless it was desired to secure a regulus of antimony alone from a given antimonial ore.
From De Re Metallica, Translated from the First Latin Edition of 1556 by Agricola, Georgius
Regulus aims this year to start work on a site to produce triple-base propellant, a particularly powerful variant that the U.S. hasn’t produced since 1986, Somerindyke said.
From The Wall Street Journal ● Jul. 28, 2026
Some standouts: Regulus Therapeutics went up 120%; 89bio went up 85%; Chimerix gained 69% and Intra-Cellular Therapies rose 57%.
From MarketWatch ● Nov. 3, 2025
The trio will shine brightly, but Venus will outshine the other two, and Regulus will be emanating a blue-white hue.
From Los Angeles Times ● Dec. 17, 2024
The meteors will appear to radiate from the head of the lion, just above Regulus.
From BBC ● Nov. 17, 2024
“Master Regulus told Kreacher to come back,” he repeated.
From "Harry Potter and the Deathly Hallows" by J.K. Rowling
The Vulgate has it, "in caverna reguli;" which, however, is not classic Latin.
From The Grammar of English Grammars by Brown, Goold
Mr. Ray himself had no knowledge of this bird, but received his account from Mr. Johnson, who apparently confounds it with the reguli non cristati, from which it is very distinct.
From The Natural History of Selborne, Vol. 1 by Morley, Henry
These ealdermen, or earls, were honoured with titles of reguli subreguli, principes, patricii, and some times rex.
From The Mirror of Literature, Amusement, and Instruction Volume 13, No. 357, February 21, 1829 by Various
Mr. Ray himself had no knowledge of this bird, but received his account from Mr. Johnson, who apparently confounds it with the reguli non cristati, from which it is very distinct.
From The Natural History of Selborne by White, Gilbert
In the middle of the ninth century, Harold Harfager, one of the reguli of Norway, subdued the other petty rulers, and made himself king of the whole country.
From Notes and Queries, Number 182, April 23, 1853 A Medium of Inter-communication for Literary Men, Artists, Antiquaries, Genealogists, etc. by Bell, George
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