Sunset refers to the daily disappearance of the sun below the horizon as a result of Earth's rotation.
The term "sunset" is also used metaphorically to describe:
1. The decline or end of something (e.g., "the sunset of one's career")
2. A color gradient resembling the colors of a sunset
3. In law, "sunset clause" refers to a provision that automatically terminates a law or program on a specific date
4. In photography, the "sunset mode" is a camera setting optimized for shooting at dusk