Reorg (Blockchain Reorganization)
Also known as: Blockchain Fork Correction, Chain Reorganization, Temporary Blockchain Fork
A temporary blockchain fork where a previously accepted chain segment is replaced by a longer competing version.
A reorg, short for reorganization, occurs when a blockchain temporarily forks and a longer competing chain replaces previously accepted blocks. This typically happens when two miners find blocks at the same height, and the network eventually converges on the longest chain. Reorgs are common in Proof of Work systems and can range from a single block to several, depending on network conditions. While often harmless, deep reorgs can disrupt dApps, lead to double-spending, and erode trust. Mitigations include finality thresholds, block confirmations, and consensus improvements.