A Block is a group of sets.
Blocks are commonly named the same way as the first set of that particular block, For example, Khans of Tarkir is the first set in the Khans of Tarkir block, preceding Fate Reforged and Dragons of Tarkir.
When a new block is released, the block of sets can lose their legality in a tournament format. There are different tournament versions that allow more cards as the tournament styles progress in type, and therefore, generality.
List of Blocks
| Ice Age • Mirage • Tempest • Urza's • Masques |
Invasion • Odyssey • Onslaught • Mirrodin • Kamigawa
Ravnica • Time Spiral • Lorwyn • Shadowmoor • Shards of Alara
Zendikar • Scars of Mirrodin • Innistrad • Return to Ravnica • Theros
Khans of Tarkir • Battle for Zendikar • Shadows over Innistrad • Kaladesh