cargo vs payload

cargo and payload both are nouns.

Word	Noun	Adjective	Verb	Adverb
cargo	Yes	No	No	No
payload	Yes	No	No	No

As nouns, cargo and payload are synonyms defined as:

Other synonyms of cargo include consignment, freight, lading, load, loading, shipment.

cargo (noun)	payload (noun)
goods carried by a large vehicle	goods carried by a large vehicle
	the front part of a guided missile or rocket or torpedo that carries the nuclear or explosive charge or the chemical or biological agents