Orphan Block

An orphan block (also known as a stale block) is one that has not been accepted by a blockchain network due to the lag time that occurs when two blocks are mined concurrently. In theory, a soft fork is created when two blocks are mined at the same time, but in practice, orphaned blocks typically only create four blocks in a row outside of the main network from which they originated. Orphaned blocks are valid and verified blocks that exist independently of the original blockchain and serve no purpose after being rejected.