a box for a book or set of books, open on one side so that the spine is visible.
Origin of slipcase
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
a protective case for a book or set of books that is open at one end so that only the spines of the books are visible
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012