It refers to the items which are now stored in a warehouse or another place, but will never be used again for the reason of engineering change or production stoppage, or have lost their own function due to some damage caused by poor storage conditions, which shows the items have no possibility of being used in the future. Compared with this, the items which have not been used for a long time, but have some possibility of being used as production parts or service parts again, and their function is enough to be used are called Sleeping Stock, Dormant Stock, Sleeping Inventory, they are differentiated from Dead Stock.

Unplanned engineering changes lead to the increase of dead stock, and thus it is crucial to detect the inventory goods which have not used for a long time as soon as possible and make a positive use of them in order not to make them to be dead.