A partial is freight that doesn’t fill a whole trailer, so a carrier pairs it with other partial shipments to make up a full truck. Each customer pays for the portion of space and weight their goods take up.
Partials help fill capacity that would otherwise run empty, but they come with a trade-off: combining several shipments usually means multiple stops, so transit can take longer than a single point-to-point load. Dispatchers weigh the added revenue against the extra time and handling.