What is Orphan Block?

An orphan block (generally referred to as a stale block) is a block that has not been accepted within a blockchain network due to the lag time when two blocks are mined simultaneously. Theoretically, a soft fork is created when two blocks are mined at the same time, but this is only a practicality because orphaned blocks typically only create four blocks in a row outside of the main network they originated from. Orphaned blocks are valid and verified blocks that exist in isolation from the initial blockchain and serve no purpose after they are rejected.