metalloid /ˈmɛtəlɔɪd/noun 3adjective 2forms 3 noun3 •An element, such as silicon or germanium, intermediate in properties between that of a metal and a nonmetal; especially an elemental semiconductor. •(no longer used) The metallic base of a fixed alkali, or alkaline earth; applied to sodium, potassium, and some other metallic substances whose metallic character was supposed to be not well defined.By some they [metals of the alkalies] were called metalloids; by some their simple nature was objected to — 1836 •(no longer used) A nonmetal. adjective2 •Of or relating to the metalloids. •(informal) Characteristic of the metal music genre.It expanded from bleary delay rippling with looped phrases to embrace molten metalloid raunch and blues grit, acoustic guitars and pedal steels. — 2004 formsmetalloids · more metalloid · most metalloid