| 1. | the setting or descent of the sun below the horizon in the evening. |
| 2. | the atmospheric and scenic phenomena accompanying this. |
| 3. | the time when the sun sets. |
| 4. | the close or final stage of any period. |
| 5. | (of an industry, technology, etc.) old; declining: sunset industries. |
| 6. | of, pertaining to, or characteristic of a sunset law: to add sunset restrictions to a bill. |