<p><strong>Noun:</strong></p><ul><li>Chemistry: a dark-gray or silvery, lustrous, very hard, light, corrosion-resistant, metallic element, occurring combined in various minerals:<ul><li>Used in metallurgy to remove oxygen and nitrogen from steel and to toughen it.</li><li>Symbol: Ti</li><li>Atomic weight: 47.90</li><li>Atomic number: 22</li><li>Density: 4.5 at 20°C</li></ul></li></ul>