Cargo, also known as freight, originally referred to items being loaded into a ship. However, in modern times, all forms of commodities, whether they be transported by truck, van, train, or intermodal container, are referred to as cargo. Although "cargo" refers to all items in a transport vehicle, it does not include things like personnel bags, items in the storage, equipment, or supplies taken on board to support the transport. The primary purpose of transporting cargo is commercial, for which the carrier issues an air waybill, bill of lading, or other receipt.

Most shipments consist of boxes or containers packed with goods being delivered from one business to another; but, when all forms of freight are included, person-to-person travel makes up a sizable fraction of international shipping. Although local freight shipments predominate, international cargo shipments are also frequent due to commercial market globalization. Shipping containers are frequently examined and sampled for security and product management purposes.

Freight sampling often entails checking boxes or shipping containers at various stages of the cargo. The results of these inspections, which are typically carried out on random containers, are communicated to both the shipper and the recipient. Larger businesses may employ their own staff to collect samples, although the task is frequently outsourced to private contractors with industry expertise.