regulus noun. ['rɛgjʊlǝs] Pl. -luses, -li [-lʌɪ, -li:]. L16.
[Latin, dim. of reg-, rex king.]
1. Chemistry. A metallic form of a substance obtained by smelting or reduction. Freq. attrib. or with of; orig. in regulus of antimony, metallic antimony (app. so called because it combined readily with gold). Now arch. or Hist. L16.

2. A petty king or ruler. L17.

3. A bird of the genus Regulus, a kinglet; orig. spec. the goldcrest. E18.

■ reguline adjective (Chemistry, now rare or obsolete) of, pertaining to, or of the nature of a regulus M17.

[TahlilGaran] English Dictionary ▲