English also has words for this concept - "reading backlog" and "unread books piling up". The Japanese term 'tsundoku' is mainly notable because it's a pun por

English also has words for this concept - "reading backlog" and "unread books piling up". The Japanese term 'tsundoku' is mainly notable because it's a pun portmanteau of 'tsunde oku' (piling up) and 'doku' (reading).