[ 'rɛgjʊləs ]
■ noun ( plural ~es or reguli -lʌɪ , -li: ) Chemistry, archaic a metallic form of a substance, obtained by smelting or reduction.
Origin
C16: from L., dimin. of rex , reg- 'king'; orig. as ~ of antimony , appar. so named because of its readiness to combine with gold.