The term 'Lorry Quartet' refers to four components of a lorry, which are the tyres, engine, cab and body. The tyres are the most important part of a lorry, as they provide traction and support for the vehicle. The engine is responsible for powering the lorry, while the cab provides the driver with a comfortable place to sit and operate the vehicle. Finally, the body of the lorry is the outer shell that protects the other components from the elements. All four components are essential for a lorry to function properly.