Final answer:
Safety stock is the inventory that companies hold to protect themselves against uncertainties in either demand or replenishment time.
Step-by-step explanation:
The inventory that companies hold to protect themselves against uncertainties in either demand or replenishment time is called safety stock. Safety stock is a buffer of extra inventory that is maintained to prevent stockouts and ensure customer satisfaction. It acts as a cushion to absorb any unexpected fluctuations in demand or delays in replenishment.