There are four quantum numbers in chemistry. These are the principal quantum number, the angular momentum quantum number, the magnetic quantum number, and the spin quantum number. These all follow these three foundational rules in chemistry.

The Pauli exclusion principle states that if two electrons inhabit the same orbital, they will spin in different directions.

Hund's rule states that if an orbital does not have an electron, an electron will need to fill it first before any of the other orbitals can have two electrons of differing spins.

The Aufbau principle states that all electrons will fill orbitals in an orderly fashion based on the quantum numbers. An attachment is included of this fill order for your reference.

The four quantum numbers for chemistry are:

The principal quantum number describes the sublevel in which the orbital is located. This occurs at n = 1, 2, 3, etc. all the way to 7.

The angular momentum quantum number describes the orbital that an electron fills. It will refer to the shape and the type of orbital.

The magnetic quantum number refers to the orientation of an orbital. Based on the angular momentum quantum number, there can be 1, 3, 5, or 7 orientations.

The spin quantum number refers to the Pauli exclusion principle. This number is assigned a negative or positive based on the orientation of the electron.

Therefore, because the magnetic quantum number is the one that refers to the orientation of the orbital, this is our answer.