What time is dinner?

Culled from the far-too-chatty chat logs of Cerulean and Fyn, which I often threaten to post here if only because ZOMGWTFBBQGUYSWENEEDTOPOSTANDNOTJUSTTALKABOUTPOSTING:

Me: ps: http://thepioneerwomancooks.com/

I'm making those damn mountain dew apple dumplings. oh, yes.

Fyn: oh hey, i was just thinking, we'd have to cook at eka's if we cook for them

that's cool w/ you, right?

me: Oh, you mean next Sunday?

Fyn: yup

i remembered that ben sleeps at 6 and we'd have to do it at their place if we were to make dinner

me: oh, we were going to do this at actual dinnertime?

("dinner" is a word whose meaning changes depending on what day it is. On Sunday, dinner is the meal you eat at 2 or 3.)

Fyn: really?

wow!

but then don't you get hungry at 7?

me: I just grew up that way. You eat dinner every night, but on Sundays you have Sunday Dinner, and that's in the afternoon.

Then you watch football or do homework and have leftover rolls or something in the evening.

I'm gonna go with this being an upbringing thing. And I will bet you dollars to donuts if you ask Wino what TIME her grandma's sunday dinners are, it'll be in the afternoon.

me: then you have a light supper.

So, what does dinner mean, then?