motor neuron vs neuron

motor neuron and neuron both are nouns.

Word	Noun	Adjective	Verb	Adverb
motor neuron	Yes	No	No	No
neuron	Yes	No	No	No

As nouns, neuron is a hypernym of motor neuron; that is, neuron is a word with a broader meaning than motor neuron:

motor neuron: a neuron conducting impulses outwards from the brain or spinal cord
neuron: a cell that is specialized to conduct nerve impulses

Other hypernyms of motor neuron include nerve cell.

motor neuron (noun)	neuron (noun)
a neuron conducting impulses outwards from the brain or spinal cord	a cell that is specialized to conduct nerve impulses