Our experience shows that every so often people use these two concepts as if they were synonymous, however, they are distinct terms and mean something completely different. Let's look at differences in bookingkit:
If you cancel an order, you can choose whether it is to be reimbursed. You can specify the amount and refund method (monetary refund or in form of a voucher).
You can cancel either the whole order (1), an individual booking (2), a whole date or one or more participants (3) - with or without a refund.
You can also make a refund to your customers without cancelling the order, for instance if a customer brings a voucher with him to the venue, and wants to redeem it. Simply add the voucher to the order by clicking on Edit and reimburse your customer by clicking on the green button Refund (4).