A pre-order is a product purchased in advance. Pre-Orders are set to ship at a later date, always noted on the product page. Please take note of your pre-order ship date when placing an order.
For example, Product X is a pre-order item. I placed an order for Product X on May 13. The pre-order ship date is June 1. When I complete my purchase, I am fully aware Product X will not ship until June 1.