Longman Dictionary of Contemporary English
WordNet
n. luggage that is light enough to be carried by hand
Wikipedia
The term hand luggage or cabin baggage (also commonly referred to as carry-on in North America) refers to the type of luggage that passengers are allowed to carry along in the passenger compartment of a vehicle instead of moving to the cargo compartment. Passengers are allowed to carry a limited number of smaller bags with them in the vehicle and contain valuables and items needed during the journey. There is normally storage space provided for hand luggage, either under seating, or in overhead lockers. Trains usually have luggage racks above the seats and may also (especially in the case of trains travelling longer distances) have luggage space between the backs of seats facing opposite directions, or in extra luggage racks, for example, at the ends of the carriage near the doors.