C fiber

C fiber

n.
Any of the unmyelinated fibers, 0.4 to 1.2 micrometers in diameter, conducting nerve impulses at a velocity of 0.7 to 2.3 meters per second.
The American Heritage® Medical Dictionary Copyright © 2007, 2004 by Houghton Mifflin Company. Published by Houghton Mifflin Company. All rights reserved.