motor neuron vs nerve cell

motor neuron and nerve cell both are nouns.

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

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

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

Other hypernyms of motor neuron include neuron.

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