Tsundoku

Tsundoku (積ん読) is the phenomenon of acquiring reading materials but letting them pile up in one’s home without reading them. The term is also used to refer to unread books on a bookshelf meant for reading later.

The term originated in the Meiji era (1868–1912) as Japanese slang. It combines elements of the terms tsunde-oku (積んでおく, “to pile things up ready for later and leave”), and dokusho (読書, “reading books”).