@WokingWriter asked: why is it called a shipment when taken by land and cargo by boat? 😉
I’m not sure that distinction exists, but there is still a distinction between them.
Shipment comes from the verb to ship which is, unsurprisingly, the same word as a ship (or, ‘boat’). It’s a Germanic word, and came into English with the Anglo-Saxons. Old Norse, the language of the Vikings, has skipa, and, before the Germanic tribes all split up, these would have been the same word.
Use of to ship meaning ‘to export, to send out by ship’ increased from the 1400s as trade with other countries was done by ship. Shakespeare used it a lot: ‘Andronicus would thou were shipt to hell’.
The rise of rail in early 1800s meant an extension of the word’s use to include the sending of things by other means, and shipping can now be used to talk about sending any kind of thing using any method. This is called semantic expansion.
Cargo is a much later word. It came into English in the 1600s from Spanish. It was chiefly used for boat-based transport but is now also used for big lorry stuff and cargo planes. The distinction between shipments and cargo has now become one of size. You can order a book from Amazon and it’s called a shipment, but cargo is just big, freight stuff. I think this is probably due to how common ship is – everyone uses it – whereas cargo is still specialist, more industrial, and used for less everyday things.
This might be because it arrived later and it was still a specialist word mostly used by sailors and people who wrote about boaty things. Ship, on the other hand, was used by everybody, so when normal people needed a word to talk about transporting stuff, they adapted the word that was already in use.