any of several compounds that form the protein component of the light-sensitive retina pigment, rhodopsin.
Origin of opsin
First recorded in 1950–55; probably back formation from rhodopsin
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
the protein that together with retinene makes up the purple visual pigment rhodopsin
Word Origin for opsin
C20: back formation from rhodopsin
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
A protein of the retina, especially the protein constituent of rhodopsin, that makes up one of the visual pigments.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.