A Full Size Run refers to when a retail store or seller has every size of a particular sneaker model available for purchase. It means that customers have the option to buy their desired size of the sneaker, rather than having to settle for a different size due to limited availability. This term is commonly used in the sneaker community and is often used to describe a store that has a wide range of sizes available for a specific sneaker release. This can be especially important for limited edition or highly sought-after sneaker releases where certain sizes tend to sell out quickly.