Definition & Meaning of "octavo"

What is "octavo"?

Octavo is a book size where each page measures approximately 6 inches by 9 inches, or 150 mm by 230 mm. It is created by folding a standard sheet of paper three times, resulting in eight sections that together make sixteen pages. This method produces a compact and practical book format, commonly used for various types of books, including novels, biographies, and academic texts. It provides a good balance between readability and portability.