v.1. To examine something or a group of things: I checked through the drawer to see if I had left my keys there.
2. To allow someone to pass through some place after examining tickets, papers, or passes: The security guards checked us through the gate.
3. To have someone's travel be arranged so that the traveller may present a ticket or check in only at the beginning of a journey and not at each leg: You don't need to go to the ticket counter when you change planes; we already checked you through.
4. To have something, especially luggage, sent along each leg of a journey to some destination, without requiring that a person pick it up and check it again at each leg of the journey, as when changing airplanes, trains, or buses: You should check your luggage through, or else you'll have to carry your bags with you in the airport.