8vo vs octavo

8vo and octavo both are nouns.

Word	Noun	Adjective	Verb	Adverb
8vo	Yes	No	No	No
octavo	Yes	No	No	No

As nouns, 8vo and octavo are synonyms defined as:

8vo and octavo: the size of a book whose pages are made by folding a sheet of paper three times to form eight leaves

Other synonyms of 8vo include eightvo.

8vo (noun)	octavo (noun)
the size of a book whose pages are made by folding a sheet of paper three times to form eight leaves	the size of a book whose pages are made by folding a sheet of paper three times to form eight leaves