<p><strong>Noun:</strong></p><ul><li>The setting or descent of the sun below the horizon in the evening.</li><li>The atmospheric and scenic phenomena accompanying this.</li><li>The time when the sun sets.</li><li>The close or final stage of any period.</li></ul><p><strong>Adjective:</strong></p><ul><li>(of an industry, technology, etc.) old; declining: sunset industries.</li><li>Of, relating to, or characteristic of a sunset law: to add sunset restrictions to a bill.</li></ul>