What is "spin quantum number"

n. (context physics English) A quantum number that specifies the spin of a particle; for an electron, it may only take the values ±1/2

In atomic physics, the spin quantum number is a quantum number that parameterizes the intrinsic angular momentum (or spin angular momentum, or simply spin) of a given particle. The spin quantum number is the fourth of a set of quantum numbers (the principal quantum number, the azimuthal quantum number, the magnetic quantum number, and the spin quantum number), which completely describe the quantum state of an electron. It is designated by the letter . It describes the energy, shape and orientation of orbitals.