thinking cap
nounUS, UK /ˈθɪŋkɪŋ ˌkæp/
Etymology Probably by analogy with considering cap, which is attested from the early 17th century.
1
Humorous, Idiomatic A metaphorical state of focused thinking or concentration, invoked to encourage problem-solving.
- This project looks like it will be a real challenge – put on your thinking cap!
- Now suppose they put on their "thinking-caps" a moment or two, and consider what is going on in the great world around them. [...] Before you pull off your "thinking-cap" cast a look around your own country—free, prosperous, powerful, independent; yet how full of wickedness, and how unmindful of its obligation to the God of nations!1855 February 28, “On with Your Thinking-caps!”, in Youth’s Penny Gazette, volume XIII, number 5 (number 317 overall), Philadelphia, Pa.; New York, N.Y.; Boston, Mass.: American Sunday-School Union, →OCLC, page 18, column 1:
4 more examples
- Come children, gather around the desk, and we will have a chat for half an hour. We want you to put on your thinking caps, and show what manner of boys and girls you are.1862 April, “Putting on the Thinking Caps”, in The Student and Schoolmate, and Forrester’s Boys and Girls Magazine, volume XL, number IV, Boston, Mass.: Galen James and Company, […], →OCLC, page 109:
- The story you shall have, then, just as well as I can tell it: and you must put on your thinking-caps, so as to remember all you can of it; and be sure to ask questions about what you don't understand.1864, William M. Thayer, “Introduction”, in A Child’s History of the Rebellion, from the Bombardment of Fort Sumter to the Capture of Roanoke Island, Boston, Mass.: Walker, Wise, and Company, […], →OCLC, page 24:
- "Costly gifts, my dear child, are not always acceptable as a proof of love. And if you put on your thinking cap, perhaps you will find that you, too, can take an acceptable keepsake to your teacher." / "Why, I'm sure I've nothing worth taking to her, mamma. And all the thinking caps in the world can't help me to an idea."1873 October 11, “Jessie’s Token of Love”, in The Temperance Record: The Organ of the National Temperance League, number 914, London: Published for the National Temperance League by William Tweedie, […], →OCLC, page 485, column 2:
- As time passed the Great Spirit grew fonder and fonder of his good-natured friend, and was grieved to see him suffer for the lack of a full dinner pot and stomach, so the Great Spirit put on his thinking-cap and learned a way to help Mr. Turtle. "The old fellow needs a wife!" said the Great Spirit taking off his thinking-cap.1916, Sara H. Merrill, “The Hero Turtle”, in John Martin [pseudonym; Morgan van Roorbach Shepard], editor, John Martin’s Annual: A Jolly Big Book for Little Folks, Garden City, N.Y.: Published by John Martin’s House Inc. […] for Platt & Peck Co., →OCLC: