0 the day of the week after Saturday and before Monday, when most people in Western countries do not go to work:
They go to church on Sundays.
I haven't done any exercise since last Sunday.
a traditional British Sunday lunch of roast beef and vegetables
1 the day of the week after Saturday and before Monday
Why don't you come for lunch on Sunday.
What shall we have for Sunday lunch.
It's my birthday next Sunday.