folio

1. N-COUNT A folio is a book made with paper of a large size, used especially in the early centuries of European printing. (尤指欧洲早期印刷的)对开本

Richard told me of three 16th-century folio volumes on alchemy. 理查德告诉过我16 世纪的关于炼金术的三卷对开本书籍的事。