bound book; codex
Refers to a book with pages bound together, typically contrasted with scrolls or other formats. Common in library and historical contexts.
Many old bound books are kept in the library.
Compound of 冊子 (sasshi, 'booklet') and 本 (hon, 'book'), both Sino-Japanese elements. The exact historical derivation is uncertain, but the term clearly refers to a book in codex form.