Glossary
Terms & Glossaries of Shipping and Trading
"Top off" means the process of adding additional cargo or goods to a shipment that is already partially loaded, in order to maximize the use of available space and reduce transportation costs. In this case, "top off" refers to filling the remaining space in a container or trailer with additional cargo.
This typically occurs where there is a draught restriction at the first load port—the ship loads a quantity of cargo corresponding to the permissive draught, then fills up at the second port where there is no restriction.