Book into Definition 1 of 2Pro Tip 1/3Service Requirement Used when a service needs to be scheduled in advance, like a hotel stay. We'll need to book into the bed and breakfast early. Pro Tip 2/3Personal Involvement Implies you're personally taking action to secure accommodation or service. I'll book us into the medical center for the appointment. Pro Tip 3/3Confirmation Indicates the act of finalizing or confirming a place in a facility. She booked into her preferred spa for the weekend.