FIFO stands for "First In, First Out", and is a type of inventory or job processing method used when assigning resources. The idea is that the person or item "first in" is the first one "out". This principle is often used in warehouses, assembly lines, and hospitals, when storing or distributing items, or when scheduling jobs. In inventory management, FIFO ensures that the items that are first purchased are the first sold and used, thus reducing the chance of them expiring or deteriorating. In job processing, FIFO ensures that the oldest task is the first to be completed.