Noun
English Wikipedia has an article on:magnetic quantum numberWikipedia
magnetic quantum number (plural magnetic quantum numbers)
(physics) A quantum number of an atomic orbital, whose possible values are related to the azimuthal quantum number, that denotes the energy levels in a subshell.
For all pictures the magnetic quantum number m has been set to 0, and the cross-sectional plane is the xz-plane (z is the vertical axis). Source: Internet
The magnetic quantum number measured the tilt of the orbital plane relative to the xy-plane, and it could only take a few discrete values. Source: Internet