a curved mirror or other optical device for giving a correct image of a picture or the like distorted by anamorphosis.
Origin of anamorphoscope
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
an optical device, such as a cylindrical lens, for correcting an image that has been distorted by anamorphosis
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