Difference between 傍晚 and 晚上 and their etymology As in the title. Are there any cases when these two are interchangeable? If yes, when? What are the nuances that distinguish them? It would be great if one can tackle the etymology of the two.
傍

　1. 靠：依山～水。
　2. 临近：～晚。～黑。～亮。
汉英互译
◎ 傍
be close to　　　draw near
English
by side of, beside, near, close

傍晚

[evening;at dusk (nightfall);toward evening] 靠近晚上的时候。亦称“黄昏”

傍晚 basically is compromised of 傍 &quot;close (to)&quot; + 晚上 &quot;nighttime&quot;
晚上

[evening;night] 从日落或晚饭至寝宴的一段时间

The Chinese literally says night is beginning at nightfall or dinner time.
晚

太阳落了的时候

time after sunset

as to whether they are interchangeable or not, well this really depends on the cognitive abilities of each person - my dusk might be your nighttime - it's hard to say for sure.

as for the entomology of 晚 Outlier says:

COMPONENTS
日 In 晚, 日 is a semantic component.
免 In 晚 wǎn, 免 miǎn is a sound component, though this is not obvious in modern Mandarin.