wreckage vs jetsam

wreckage and jetsam both are nouns.

Word	Noun	Adjective	Verb	Adverb
wreckage	Yes	No	No	No
jetsam	Yes	No	No	No

As nouns, jetsam is a hyponym of wreckage; that is, jetsam is a word with a more specific, narrower meaning than wreckage:

Other hyponyms of wreckage include flotsam, lagan, lagend, ligan.

wreckage (noun)	jetsam (noun)
the remaining parts of something that has been wrecked	the floating wreckage of a ship
	the part of a ship's equipment or cargo that is thrown overboard to lighten the load in a storm