possessor vs shipowner

possessor and shipowner both are nouns.

Word	Noun	Adjective	Verb	Adverb
possessor	Yes	No	No	No
shipowner	Yes	No	No	No

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

Other hyponyms of possessor include holder, homeowner, householder, part-owner, saver.

possessor (noun)	shipowner (noun)
a person who owns something	someone who owns a ship or a share in a ship