指一个会计期间内，期初可供使用或出售的商品、物资或原料等存货的价值，在数量上等同于上期的期末存货，通常反映在损益表中，是计算当期销售成本的依据。

The book value of goods, inputs, or materials available for use or sale at the beginning of an inventory accounting period.

Beginning inventory is similar to ending inventory except that it is adjusted for any accounting discrepancies. BI is an important figure for companies because they use it to gauge new ordering requirements and to forecast future sales. Company managers can be evaluated based on their levels of beginning inventory and inventory turnover.