Principal direction of movement for customer orders which originate at point of demand or use, as well as other flows, such as return product movements, payments for purchases, etc. Opposite of downstream.

Warehouse Bin Storage System Best Practices: Optimizing Your Warehouse Layout
Keeping a warehouse neat and organized isn’t just for show—it’s essential if you’re managing tons of products every day. A messy layout slows everything down, causes costly mistakes, and frustrates your team. On the flip side, a smartly organized bin storage system can turbocharge your warehouse’s efficiency. Let’s walk through