- a state of mind marked by reflection or concentration: If we put on our thinking caps, we may come up with the answer.
Origin of thinking cap
First recorded in 1870–75
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018
Examples from the Web for thinking cap
Now here's my idea that I evolved with my thinking-cap—I mean night-cap—on!Glory and the Other Girl
Annie Hamilton Donnell
"And this head of mine would have to put on its thinking-cap," he pursued jovially.The Leavenworth Case
Anna Katherine Green
We are a little too inclined to doff the thinking-cap at the first opportunity.The Secrets of a Savoyard
Henry A. Lytton
But I had my New England "thinking-cap" firmly set on my shoulders.Geraldine Farrar
Tell me what you know and then my 'thinking-cap' may be put on to some advantage.Kitty's Conquest
Idioms and Phrases with thinking cap
The American Heritage® Idioms Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.