This is the 4615th most frequent Arabic word.
إضافي
Additional.
Here, 'إضافي' describes the additional or extra seat required.
أحتاج إلى مقعد إضافي لطفلي.
I need an additional seat for my child.
In this instance, 'إضافي' refers to the order being extra or additional to the original request.
قدّم النادل طلبًا إضافيًا بدون أن نسأله.
The waiter provided an extra order without us asking.
Here, 'إضافي' describes the effort as being more than the usual or required amount.