Is ‘next Sunday’ the one coming up or the one after?

[user9812]

Just that really. If today is Wednesday and someone refers to ‘next Sunday’ do they mean the one in 4 days time or 11 days time? I assumed 4 days time.

Thinking about this, I have always used "this Sunday" to mean the Sunday closest today, whether the one just past or the one coming up. Certainly, if I were speaking on a Monday, the next Sunday to come up would be "next" Sunday to me, not "this" Sunday. But I do usually include lots of other signals about which day I mean because I've noticed a lot of people use the words differently.