Bible Dictionaries
Octavo

Webster's Dictionary

(1):

(n.) 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¡.

(2):

(a.) Having eight leaves to a sheet; as, an octavo form, book, leaf, size, etc.

Bibliography Information
Webster, Noah. Entry for 'Octavo'. Noah Webster's American Dictionary. https://www.studylight.org/​dictionaries/​eng/​web/​o/octavo.html. 1828.