Apre-orderis
an order placed for an item which has not yet been released. The idea
for pre-orders came when people found it hard to get popular items in
stores due to their popularity. Companies then had the idea to allow
customers to reserve their own personal copy, before the release, which
has been a huge success.
Preorders
allow consumers to guarantee immediate shipment on release,
manufacturers can gauge how much demand there will be and hence the size
of initial production runs, and sellers can be assured of minimum
sales.