It was called spin because for a time the model of an electron was a solid sphere of charge that was spinning on its axis. It was known that the electron made a

It was called spin because for a time the model of an electron was a solid sphere of charge that was spinning on its axis. It was known that the electron made a magnetic field, and since charge in motion makes a magnetic field that could be explained by a spinning electron. But if you actually do the math you'll be off by a factor of about two. Quantum mechanics had to be invented to explain this discrepancy and the name stuck.