edition vs variorum

edition and variorum both are nouns.

Word	Noun	Adjective	Verb	Adverb
edition	Yes	No	No	No
variorum	Yes	No	No	No

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

edition: the form in which a text (especially a printed book) is published
variorum: an edition containing various versions of a text or notes by various scholars or editors

Other hyponyms of edition include limited edition, variorum edition.

edition (noun)	variorum (noun)
something a little different from others of the same type	an edition containing various versions of a text or notes by various scholars or editors
an issue of a newspaper
the form in which a text (especially a printed book) is published
all of the identical copies of something offered to the public at the same time