motor neuron

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun A neuron that conveys impulses from the central nervous system to a muscle, gland, or other effector tissue.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun neuroanatomy A neuron located in the central nervous system that projects its axon outside the CNS and directly or indirectly control muscles.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun a neuron conducting impulses outwards from the brain or spinal cord