1. The origin of "at night" to indicate a point of time and the usage of prepositions "in" and"at" In olden times, when the time expression "at night" was originated, night might have been thought as a point of time in the day because there wasn't any activity going on and people were sleeping that time unlike daytime. 4 Day and night time is not an idiomatic or set phrase (unlike day and night), but it can be used appropriately in certain contexts, particularly in technical ones.

Understanding the Context

Here is a relevant usage I've found: The English word day can be used to refer to the time of daylight or to the unit of time that encompasses both day and night time. Can we use "day and night time" instead of "day and night"? “Good night” or “good evening”? I am in the process of creating a software application which displays a greeting to users based on the time of day.

Key Insights

I have come to a blank on what to display to the user when it is late at night. 'Good night, [user's name]' just doesn't seem right. So, what is an appropriate greeting to use at night time? I forgot where but I saw the word "night-time" written like "nighttime". Now is that correct or accepted?

Final Thoughts

Can it be written as a single word? I am specifically concerned about British usage. I did nouns - Can "nighttime" be used instead of "night-time"? - English ...