Octavo

n.	1.	A book composed of sheets each of which is folded into eight leaves; hence, indicating more or less definitely a size of book so made; - usually written 8vo or 8°.
a.	1.	Having eight leaves to a sheet; as, an octavo form, book, leaf, size, etc.

Noun

1.

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

8vo, eightvo, size