noun
foreign book; foreign books
General term for books from abroad, often contrasted with Japanese books (和書).
大学の図書館には多くの外書が所蔵されている。
The university library holds many foreign books.
noun
non-Buddhist writings
Buddhist term for writings outside the Buddhist canon, such as Confucian or secular texts.
僧侶は外書も学ぶことがある。
Monks sometimes study non-Buddhist writings as well.