What is a mining orphan in proof-of-work?

A mining orphan is a block that a miner validly produced but that gets discarded because the network already accepted a competing block first. In traditional proof-of-work, miners race to find one winning block; when two miners finish at nearly the same time, the network keeps only one — and all the energy that went into the losing block contributes nothing. This matters for beginners because orphaned blocks represent real wasted computation, and that waste can quietly push mining toward larger operations over time.