noun
Iwanami Junior Shinsho
A nonfiction paperback series for young readers published by Iwanami Shoten. The name is a proper noun referring to the imprint itself.
岩波ジュニア新書は、中学生や高校生向けの入門書シリーズです。
Iwanami Junior Shinsho is a series of introductory books for junior high and high school students.
Iwanami Shinsho is the general-audience paperback series from the same publisher, while Iwanami Junior Shinsho is specifically aimed at younger readers.
The name combines the publisher 岩波 (Iwanami) with ジュニア (junior) and 新書 (shinsho, a common term for paperback series).