By “party”, I mean a physical social gathering of people for the purposes of having fun. It may be used in a sentence as “I am throwing a party!” or “Let’s party!”.
Basically what I am trying to say is the default “party”.
I’ve never been to any, and I have no idea how people spend their time on parties, so I am curious how you did.
Not late late, just late enough that the host has had time to make sure everything is in order, or just to not be the first guest to show up.
Usually a party lasts at least a few hours, so showing up 30 minutes after the start of the party isn’t “being late,” it’s just showing up to a party in progress. Unless it’s a specifically scheduled “arrive at 8pm” kind of affair, in which case the host would mention it and you’d be expected to be there at that time.