A small bag or suitcase that a passenger is allowed to take onto an airplane. She packed her essentials in a carry-on to avoid checking luggage.
An item or piece of luggage that is permitted to be carried into the passenger compartment of a vehicle, especially an airplane. The airline has strict size limits for each carry-on.
Informal, chiefly British. Fuss, commotion, or improper behaviour. Stop all this carry-on and sit down, will you?