In Colombia is synonymous with teamster, freighter, costalero, bulteador. Person who earns his living loading or unloading vehicles.
cotero:persona having for job loading and unloading heavy objects.
Best meaning can be: Cotero m. workman in charge of loading and unloading goods from a ship, truck, van, etc.
Word currently in use which is replacing bracero. It refers to people who carry things. man of such activity