nightfall, night
晩 centers on the late part of the day when light fades: nightfall and the night that follows.
晩 is the modern Japanese simplified form of 晚. The older form combines 日 (sun) with a phonetic component that also suggests the idea of late or evening. The modern 免 shape is a simplification of that original right-side component.
The sun 日 is on the left, and the right side 免 looks like a person bending down as the day ends. Picture the sun setting and someone bowing out for the night.
For バン, imagine a van pulling up at nightfall to deliver the evening goods: van -> バン, and the sun has set.
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evening; night
good evening
every night
tonight; this evening
last night
dinner (esp. a formal one)
one's later years; final years (in life)
drink at home with one's evening meal; dinner-time drink
morning and evening
late autumn (fall)
late marriage
late summer
sooner or later; in time; eventually
great talents mature late
the last stage
late completion; succeeding later in life; being a late bloomer
evening; good evening
good evening (greeting, e.g. in emails sent in the evening)
that night; that evening
Sicilian Vespers (opera by Verdi); Vespri siciliani