Idioms — Set 21

Set 21 of Idioms covers 5 idioms: put on your thinking cap, a penny for your thoughts, think outside the box, rack your brain, split hairs. Each entry below includes its definition, an example sentence, and synonyms — practice them with the interactive cards above.

1. put on your thinking cap · idiom/pʊt ɔn jʊr ˈθɪŋkɪŋ kæp/

   to start thinking seriously about something

   We need to come up with a new strategy. Let's put on our thinking caps and brainstorm some ideas.

   Origin: From English schools in the 1800s — special caps were worn during difficult lessons to encourage concentration.

2. a penny for your thoughts · idiom/ə ˈpɛni fɚ jʊr θɔts/

   asking someone what they are thinking

   You've been so quiet. A penny for your thoughts?

   Origin: Coined by Thomas More in 1535 — a small playful offer to buy someone's silent thoughts and bring them out.

3. think outside the box · idiom/θɪŋk aʊtˈsaɪd ðə bɑks/

   to think creatively and differently from the usual way

   To solve this issue, we need to think outside the box and come up with something innovative.

   Origin: From a 1970s puzzle where solvers had to draw outside an imagined boundary to solve the nine-dot problem.

4. rack your brain · idiom/ræk jʊr breɪn/

   to think hard about something to remember or solve it

   I've been racking my brain trying to remember where I put my keys!

   Origin: From the medieval torture device 'the rack' — straining one's mind compared to stretching a body in pain.

5. split hairs · idiom/splɪt hɛrz/

   to argue about small, unimportant details

   Stop splitting hairs over minor details and focus on the bigger picture!

   Origin: From the 1600s — hair is already extremely thin, so splitting it is an image of pointless tiny distinctions.