Sunday evening is a specific day. If we were to use "the evening" on its own, it could refer to any evening, and is not therefore a specific day or date. I really do wish I could tell you "why" we use on, but it would seem to be a rather arbitrary choice, with no particular logic to it. More info here: In, at, on + Time or Date
To a large extent the start of 'evening' is a matter of opinion or convention. The Oxford Dictionaries say that it 'usually' starts at 'about' 6 PM. Note the lack of a definite rule. Evening NOUN 1 The period of time at the end of the day, usually from about 6 p.m. to bedtime. it was seven o'clock in the evening Evening (Lexico) Cambridge does not provide a time: the part of the day between ...
I wonder what the exact times of the following words are: morning, noon, afternoon, evening, night, mid-night. What's the difference between at night and in the night?
The easiest way to explain, I guess, would be to compare in the evening -> time of day vs on the evenings -> date. NB: there is no "s" in "in the evening", because it's a time frame not a series of dates.
word choice - On the evening Vs. In the evening - English Language ...
Should I refer to 16:00 o'clock as afternoon or as evening? In winter, when the days are short, and it becomes dark already at this time already in many countries, and therefore it is not clear t...