Orphan Block Definition - Glossary

Orphan Block is a valid block not accepted into the blockchain because another block was simultaneously added first.

Orphan Block is a block in a blockchain network that was mined but not accepted into the main chain. This occurs because two miners produce blocks almost simultaneously, and the network must choose one. The orphaned block is valid but excluded because another block was added to the longest chain first. Orphan blocks do not contribute to the blockchain's transaction history. They are eventually discarded as nodes reach consensus on the longest chain. Although orphan blocks don't impact the current state, their existence is a natural part of decentralized consensus mechanisms like those used in Bitcoin.