1. A disease process involving a number of peripheral nerves (literal sense).
2. A nontraumatic generalized disorder of peripheral nerves, affecting the distal fibers most severely, with proximal shading (the feet are affected sooner or more severely than the hands), and typically symmetrically; most often affects motor and sensory fibers almost equally, but can involve either one, either solely or very disproportionately; classified as axon degenerating (axonal), or demyelinating; many causes, particularly metabolic and toxic; familial or sporadic.
The information shown above for polyneuropathy is provided by Stedman's.
* Stedman's, part of Lippincott Williams & Wilkins, provide a comprehensive line of health-science publications for healthcare professionals and medical students.