<p><strong>Noun:</strong></p><ul><li>A bivalent, metallic element whose compounds resemble those of calcium, found in nature only in the combined state, as in strontianite.</li><li>Used in fireworks, flares, and tracer bullets.</li><li>Symbol: Sr; Atomic mass: 87.62; Atomic number: 38; Density: 2.6.</li></ul>