The Fender Rhodes Student Piano was a piano made for music teachers and students. It had a built-in metronome and was sold to music schools during the late sixties. It was more like a modified version of the Suitcase model, but with a futuristic curved shape and without the vibrato and tremolo. The hammer heads of felt and the tonebars were just like the ones in the earlier Suitcase models. The piano did also offer a headphone jack and a mic input.
Further research says it is a nickname invented by the persons who built it.