nerve fiber

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

• noun A threadlike process of a neuron, especially the prolonged axon that conducts nerve impulses.

from The Century Dictionary.

• noun A minute cord conveying molecular disturbance which serves as a stimulus to some peripheral active organ or to some central nervous mechanism.

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

• noun anatomy An axon.

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

• noun a threadlike extension of a nerve cell