The term 'RESERVED IN ADVANCE' can be broken down into two crossword solutions: BOOKED (6 letters) and BESPOKE (7 letters). BOOKED is a verb meaning to arrange for something to be held, saved, or set aside for a particular purpose. It is often used in the context of making a reservation for a hotel room, restaurant table, or other service. BESPOKE is an adjective meaning made to order or custom-made. It is often used to describe items such as clothing, furniture, or jewelry that are made to fit the individual's exact specifications.