Why if it is sent by boat is called cargo, but by truck its called shipment?

only serious answers pleaseWhy if it is sent by boat is called cargo, but by truck its called shipment?
because cargo is marine term. shipment could apply to any transportation mode. freight would be on a truck or rail.Why if it is sent by boat is called cargo, but by truck its called shipment?
The same reason you drive on a parkway and park in a driveway.
Someone made a mistake transposing the terms and everyone after got stuck with it.
actually, I think it is all called Cargo.. and by truck it is more ';freight'; than shipment... I think, anyway.
cargo is the term used to describe what is being hauled from point to point, the movement itself is called a shipment.





for example:





the ships cargo is coal.





we have a shipment of coal from the USG to NE coming up.