n. In ornithology: An old name of the goldcrest or crested wren of Europe; a kinglet.n. The typical genus of Regulinæ; the kinglets.n. In alchemy and early chemistry, the reduced or metallic mass obtained in the treatment of various ores, particularly those of the semi-metals (see metal); especially, metallic antimony (regulus antimonii): but various alloys of antimony, other brittle metals, and even the more perfect metals were also occasionally so called, to indicate that they were in the metallic condition.n. A very white star, of magnitude 1.4, on the heart of the Lion; a Leonis.n. In geometry, a ruled surface or singly infinite system of straight lines, where consecutive lines do not intersect.n. n. In metallurgy: The metallic mass which sinks to the bottom of a furnace or crucible, separating itself from the slag by gravity.n. An intermediate product obtained in smelting ores, especially those of copper, lead, silver, and nickel, and consisting chiefly of metallic sulphids.n. One set of generators of a quadric surface; the system of straights that meet three non-incident straights.n. A configuration of lines which satisfy three conditions, and therefore depend on only one parameter.