a talk or lecture in which the speaker illustrates points by drawing on a blackboard: The coach gave a chalk talk before the big game.
Origin of chalk talk
An Americanism dating back to 1830–40
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
US and Canadian an informal lecture with pertinent points, explanatory diagrams, etc, shown on a blackboard
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