Chain Reorganization
A network event where the active chain tip switches to a different branch with more accumulated work.
- Also known as
- Chain ReorgReorg
A reorg happens when two valid chains compete and the network adopts the one with more accumulated proof-of-work. Transactions in the orphaned blocks return to the mempool if not included in the new chain.
Small reorgs (e.g., 1–2 blocks) can occur naturally when blocks are found close together. Deep reorgs are rare and may indicate an attack or severe network partition. During a reorg, previously seen confirmations are reduced, so merchants often wait for multiple confirmations for high-value payments.
Related terms
4 linkedExplore connected entries beyond the alphabetical index.
Block
→A batch of valid transactions added to a blockchain, linked to the previous block by a cryptographic hash.
Confirmations
→The count of blocks confirming a transaction, usually including the block that first contains it.
Orphan Block
→An orphan or stale block is a valid block that is not part of the chain with the most accumulated work.
Majority Attack
→A potential attack on a blockchain network where a single entity gains control of the majority of the network's hash rate.
All terms and definitions may update as the Cryptionary improves.
