The extension is an extra day. For example; we stay at the hotel for a night. But we want to stay one more day. So, we will extend our day and update check out date. Another example: We have a rental car from Istanbul. We used it 4 days. We want to use it two days more. For these two days, we will request an extension.
What does Mean “Extension” in Other Languages?
Al Bakiyye (ᒍ Ḷ⟓৬)