@headword
Also
i morgen - tomorrow
i morgen tidlig - tomorrow morning
i går morges - yesterday morning

Evenings:
I aften - today's evening
I (går) aftes - yesterday's evening
I morgen aften - tomorrow's evening
her til aften - the evening currently ongoing, just past or just about to begin

Likewise afternoon: i (går) eftermiddags, i morgen eftermiddag, her til eftermiddag.

Forenoon - formiddag (about 9-12), same system. Or midday, middag(s).

But if you invite someone "til middag" it's for a big warm meal, almost always supper because we switched the timeslot of our big warm meal....
@wannabemystiker @kennethk