Meld cards have a Magic card face on one side and half of an oversized card face on the other.
July 23, 2021 · Adventures in the Forgotten Realms
Each face of a double-faced card has its own set of characteristics.
July 22, 2016 · Eldritch Moon
If a melded permanent leaves the battlefield, one permanent leaves the battlefield and two cards are put into the appropriate zone.
February 1, 2014 · Born of the Gods
If information about an object would be visible to the player being controlled, it’s visible to both that player and the controller of the player.
September 30, 2011 · Innistrad
If information about an object would be visible to the player being controlled, it's visible to both that player and the controller of the player.
April 23, 2010 · Rise of the Eldrazi
rule 712.4 not present in this release
February 1, 2010 · Worldwake
All objects in the main game and all cards outside the main game are considered outside the subgame (except those specifically brought into the subgame). All players not currently in the subgame are considered outside the subgame.