slave owner vs holder

slave owner and holder both are nouns.

Word	Noun	Adjective	Verb	Adverb
slave owner	Yes	No	No	No
holder	Yes	No	No	No

As nouns, holder is a hypernym of slave owner; that is, holder is a word with a broader meaning than slave owner:

slave owner (noun)	holder (noun)
someone who holds slaves	a holding device
	the person who is in possession of a check or note or bond or document of title that is endorsed to him or to whoever holds it
	a person who holds something