이번주(i-beon-ju, ibeonju)
Refers to the current week including today.
When to use
Current week schedule, Meeting this week, Weekend plans including today
The nuance
‘이번주’ indicates the week that includes today, so use it when referring to the current calendar week containing the present day.
다음주(da-eum-ju, daeumju)
Refers to the week immediately after the current one.
When to use
Appointment next week, Monday of next week, Schedule after current week ends
The nuance
‘다음주’ means the week following the current week, so use it when talking about the week after this one ends.