ostiary vs Holy Order

ostiary and Holy Order both are nouns.

Word	Noun	Adjective	Verb	Adverb
ostiary	Yes	No	No	No
Holy Order	Yes	No	No	No

As nouns, Holy Order is a hypernym of ostiary; that is, Holy Order is a word with a broader meaning than ostiary:

ostiary: the lowest of the minor Holy Orders in the unreformed Western Church but now suppressed by the Roman Catholic Church
Holy Order: (usually plural) the status or rank or office of a Christian clergyman in an ecclesiastical hierarchy

Other hypernyms of ostiary include clergyman, man of the cloth, reverend, Order.

ostiary (noun)	Holy Order (noun)
someone who guards an entrance	(usually plural) the status or rank or office of a Christian clergyman in an ecclesiastical hierarchy
the lowest of the minor Holy Orders in the unreformed Western Church but now suppressed by the Roman Catholic Church