The Collaborative International Dictionary of English v.0.48:
Cargo \Car"go\, n.; pl. Cargoes. [Sp. cargo, carga, burden,
load, from cargar to load, from cargar to load, charge, See
The lading or freight of a ship or other vessel; the goods,
merchandise, or whatever is conveyed in a vessel or boat;
Cargoes of food or clothing. --E. Everett.
Note: The term cargo, in law, is usually applied to goods
only, and not to live animals or persons. --Burill.