doorkeeper vs ostiarius

doorkeeper and ostiarius both are nouns.

Word	Noun	Adjective	Verb	Adverb
doorkeeper	Yes	No	No	No
ostiarius	Yes	No	No	No

As nouns, doorkeeper and ostiarius are synonyms defined as:

doorkeeper and ostiarius: the lowest of the minor Holy Orders in the unreformed Western Church but now suppressed by the Roman Catholic Church

Other synonyms of doorkeeper include ostiary.

doorkeeper (noun)	ostiarius (noun)
someone who guards an entrance	the lowest of the minor Holy Orders in the unreformed Western Church but now suppressed by the Roman Catholic Church
an official stationed at the entrance of a courtroom or legislative chamber
the lowest of the minor Holy Orders in the unreformed Western Church but now suppressed by the Roman Catholic Church