I’m going to propose a couple of new terms that fill a gap in our available descriptions for certain times of the day.
For example, you want to meet someone at 4 or 5 pm. Would you say that you’re meeting them in the afternoon? In the evening? Over dinner? No. The first two don’t really represent the general time period that you have in mind and over dinner might suggest (perhaps incorrectly) that there’s food involved. The solution?
It’s a portmanteau of afternoon and evening that adequately describe the grey area between the two.
Similarly, but a little less elegantly, perhaps the period between what is clearly morning and what is clearly the afternoon should be called the mor·ner·noon.
Or, perhaps, I use portmanteaus a little too often and humanity has gotten us this far without such words available to them…