In your specific example though, the word day. The most likely way to express the idea would be, february 11 was really hectic, so i had to do a ton of work that day.. In the daytime or during the daytime would be a much more natural and usual construction
daytime casual looks Daytime, Casual Looks, Style, Swag, Outfits
I suspect this was devised by analogy with at night which is of course very normal.
Context can change the meaning
Deliveries will be made during the daytime, (regular occurrence in daylight hours) might be different than deliveries will be made during the. (1) i have a job during weekday daytime, not weeknights (2) i have a job during daytime weekdays, not weeknights Tell me please what is the difference between the two expressions
Additionally, eating eggs has been linked to improved cholesterol levels and weight loss None of these is something a fluent speaker would be likely to say The most likely way to express the idea would be, february 11 was really hectic, so i had to do a ton of work that day. during. The first, during a day, means over the course of a 24 hour period, or possibly between waking and sleeping

It would be used for general statements, such as those about a typical day
The day here means daytime, yes To work a day shift or schedule It does not include the night During most of the day can be.
We went to the zoo in the daytime and at night we got dinner During the day we went to the zoo If you want to combine the date and daytime constructs you would say I have a question about the meaning of all day, because day could mean both daytime = until 1800 hours or 24 hours

Let's say it started raining this morning and it is now.
In your specific example though, the word. Deliveries will be made during the daytime, (regular occurrence in daylight hours) might be different than deliveries will be made during.

