Say on the first floor of a school building, we have several classes. In front of the classes, there is a passage. So, one side of the passage are class doors and one side is a barrier. If students look down over the barrier, they see the schoolyard.
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Is the passage called a balcony or a corridor?
If the school building were just a house, I would call it balcony. But there are several classes next to each other in the above picture.
It is a corridor.
M+W defines corridor: 'a passageway (as in a hotel or office building) into which compartments or rooms open'
Collins Dictionary defines it similarly: 'A corridor is a long passage in a building, with doors and rooms on one or both sides.'
Google has a similar definition: 'a long passage in a building from which doors lead into rooms'
There may be a technical architectural term.
Most of the time you don't actually need a name for it.
If you do need to call it by something, you could use "corridor" if you are using the space as a means to walk from one room to another, or "balcony" if you are using the space as a means to look out over the courtyard.
That is you could use either word depending on context.
