<p><strong>Noun:</strong></p><ul><li>a nonmetal that in combination with a metal forms an alloy.</li><li>an element that has both metallic and nonmetallic properties, as arsenic, silicon, or boron.</li></ul><p><strong>Adjective:</strong></p><ul><li>of or relating to a metalloid.</li><li>resembling both a metal and a nonmetal.</li></ul>