Q. What is suspend/hold on reservations?
The option to suspend reservations is for when you don't want the book to be reserved for you until after a particular date, for example if you are going away for two weeks, and do not wish the item to be reserved until after you get back. The reservation does not appear on the library system until after the end of the suspension date.
The screenshot below shows a reservation that has been suspended (note the option to 'resume' it):