Sunset; the time or event when the sun goes below the horizon (same as 'sun's setting').
今日の日没は午後6時ごろだと天気予報で言っていた。
The weather report said today's sunset is around 6 p.m.
山頂で見る日没はとてもきれいだった。
The sunset viewed from the mountain summit was very beautiful.
日没後は急に気温が下がることが多い。
Temperature often drops quickly after sunset.