from The American Heritage® Dictionary of the English Language, 4th Edition

  • n. A protein of the retina, especially the protein constituent of rhodopsin, that makes up one of the visual pigments.

from Wiktionary, Creative Commons Attribution/Share-Alike License

  • n. Any of a group of light-sensitive proteins in the retina

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

  • n. retinal protein formed by the action of light on rhodopsin


Probably back-formation from rhodopsin.
(American Heritage® Dictionary of the English Language, Fourth Edition)



Log in or sign up to get involved in the conversation. It's quick and easy.