Hand baggage is baggage with the maximum of dimensions 55x40x20 cm that you are allowed to take to the cabin with you.
Hold baggage is the suitcase or suitcases that you have to pay for separately with your booking and that you have to check-in. The maximum number of hold bags that you are allowed to check in is eight (8). The maximum weight of all hold bags combined is 20 kilos.
The term ‘hold bag’ or ‘hold baggage’ comes from the definition of hold cargo, the space in a ship or aircraft for storing cargo. For the average user, in plain English, hold luggage is the suitcase that you drop on the conveyor belt in the hope that the desk attendant does not try to charge you rip-off fees for excess of weight.
Some frequent flyers of British Airways would even argue that hold baggage is the suitcase whose colour, shape and make you need to remember when you claim your compensation for lost or mishandled luggage.