Closed book
A book with the covers shut — a body of knowledge fully present and currently not being consulted.
A closed book in a dream is the dream's image of a body of knowledge fully present and currently not being consulted. The book has not been thrown out; the book is on the shelf, intact, and is not open. The dream brings the closed book when something in your life — an old skill, a body of family memory, a religious tradition you grew up inside — is available but is no longer being read. A closed book lifted again with respect, the dust blown off, is the dream affirming that the kept content can be returned to. A closed book that no one in the house any longer knows how to open, the language inside having become foreign, is the dream noting that the knowledge is still on the shelf and the access to it has been lost from the living memory of the people who own the room.