A stockroom is a room where things are kept until they are needed.
Stockrooms are usually organized and used in stores or businesses.
Examples:
The stockroom is where we keep all the extra toys.
Can you get more paper from the stockroom?
She goes to the stockroom to find the missing books.
The stockroom is like a treasure chest of things we might need.
The stockroom is so big, it's like a whole other world in there.
I like to play hide and seek in the stockroom.