archaic A metallic form of a substance obtained by smelting or reduction.→ reguline
- ‘He also bought the nearby smelting works at Scotts Creek to refine copper regulus produced at the Bremer mine.’
- ‘When it demolished the furnace in 1882 it recovered also some copper from stockpiled regulus.’
- ‘This was smelted, which reduced the bulky and heavy copper ore to a much smaller and more valuable regulus, before transporting it to the English and Australian Copper Smelting Company at Port Adelaide or to England.’
2A petty king or ruler.
- ‘The king left him as sub regulus whenever he was out of the country.’
Late 16th century: from Latin, diminutive of rex, reg- king; originally in the phrase regulus of antimony (denoting metallic antimony), apparently so named because of its readiness to combine with gold.
The brightest star in the constellation Leo. It is a triple system of which the primary is a hot dwarf star.
Latin, literally little king.