How Does the Concept of a “Share” Relate to a Miner’s Contribution in a Pool?

A "share" is a valid partial proof-of-work submitted by an individual miner to the pool operator. It proves the miner has completed work that is below the pool's target difficulty but not necessarily below the network's current difficulty.

Shares are used by the pool to measure and quantify each miner's contribution to the collective effort of finding a block. The total number of shares submitted by a miner determines their proportional payout once a block is found, depending on the payment method.