We used to call it stock. Businesses buy goods and then sell them. If they have any goods left unsold at the end of the year then they have an asset at the end of the year and it is called inventory.
I do suggest you watch the free lectures – everything is explained in detail in the lectures, and I am not going to type them all out here!! The lectures are a complete free course for Paper F3 and cover everything needed to be able to pass the exam well.