cataloguer vs cataloger

cataloguer and cataloger both are nouns.

Word	Noun	Adjective	Verb	Adverb
cataloguer	Yes	No	No	No
cataloger	Yes	No	No	No

As nouns, cataloguer and cataloger are synonyms defined as:

cataloguer and cataloger: a librarian who classifies publications according to a categorial system

cataloguer (noun)	cataloger (noun)
a librarian who classifies publications according to a categorial system	a librarian who classifies publications according to a categorial system