motor neuron vs motoneuron

motor neuron and motoneuron both are nouns.

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

As nouns, motor neuron and motoneuron are synonyms defined as:

motor neuron and motoneuron: a neuron conducting impulses outwards from the brain or spinal cord

Other synonyms of motor neuron include efferent neuron, motor nerve fiber.

motor neuron (noun)	motoneuron (noun)
a neuron conducting impulses outwards from the brain or spinal cord	a neuron conducting impulses outwards from the brain or spinal cord