- the range of wavelengths of electromagnetic radiation that is normally visible, from 380 to 760 nm.
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018
- The part of the electromagnetic spectrum visible to the human eye, extending from extreme red, 760.6 nanometers, to extreme violet, 393.4 nanometers.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.