Sun·set Sun·set·ting, n.
1. The descent of the sun below the horizon; also, the time when the sun sets; evening. Also used figuratively.
'T is the sunset of life gives me mystical lore. --Campbell.
2. Hence, the region where the sun sets; the west.
Sunset shell Zool., a West Indian marine bivalve (Tellina radiata) having a smooth shell marked with radiating bands of varied colors resembling those seen at sunset or before sunrise; -- called also rising sun.