It refers to the "object" itself such as product, assembly, part, and raw material, but generally speaking an item often refers to one of master data necessary to express B/M, which is also called I/M (Item Master) or P/M (Parts Master). In this meaning, it is a group of items which are necessary for production activities and are also unique data that can be referred by the item number.

An item has such entries as item number, item name, lot size, and lead time.