1. the descent of the Earth below the horizon as seen from the Moon or another celestial body; the moment when Earth disappears below the horizon.
Usage: astronomy; space exploration; often used in contrast with 'earthrise'

Examples

• Astronauts aboard the lunar module witnessed a spectacular earthset over the lunar horizon.
• The earthset occurred just as the sun dipped below the distant mountains of the Moon.
• From the Moon's surface, an earthset is a breathtaking sight that mirrors a sunset on Earth.
• The mission captured stunning photographs of earthset during the final hours of the lunar orbit.