Where do you determine the threshold between afternoon and evening?

I think its when I eat my supper. before supper is afternoon, after supper is evening. that is, if I eat my supper around 5 or 6 so maybe 5-6pm is about when it switches. like 4:30 is afternoon but 6 is not afternoon. 5:30 is in between, not really afternoon but not evening either.

6 PM

6pm.

Dusk.

6pm

6