Sunset; Sunsetting

Part of speech: noun (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 (Zoöl.), 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.