An LTL (Less Than Truckload) is a partial load in a truck. Generally, if a truck is only partially loaded, the company will look for other partial loads to fill it, so that the journey is worth it. Consolidated cargo is an alternative to additional partial loads.
Theoretically, of course, multiple partial loads could earn the transport company more money than a full load of the same weight and volume, however there could be long wait times at each loading and unloading point, which can cause serious delays to the transport. For particularly urgent scheduled goods, it may even by the case that a truck will have only a partial load for large parts of the journey.
Partial loading of a container is referred to as LCL (Less than Container Load).