Orphan Block (Stale Block)

When two miners solve blocks nearly simultaneously, the network briefly forks; the branch that receives the next block wins, and the loser's block is orphaned — technically "stale". Its coinbase reward never matures. Orphan rates are below 0.1% on Bitcoin but matter more on fast chains, which is why Kaspa's blockDAG includes parallel blocks instead of discarding them.

For pool miners, orphans surface as occasional invalidated earnings on transparent pools. Persistent high stale-share rates on your own rig point to network latency — mine on a pool server geographically close to you.