pertaining to or noting a lens that is plane on one side and concave on the other.
Origin of plano-concave
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
(of a lens) having one side concave and the other side plane
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
Flat on one side and concave on the other.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.