thinking cap

1. 1.

   a state in which one thinks

   Broaderstate of mind

Questions about thinking cap

What does thinking cap mean?

thinking cap means "a state in which one thinks".

Is thinking cap a common word?

thinking cap is banded "Rare" — specialist or archaic — most readers will not have met it. The band comes from how often the word appears in a large corpus of everyday English, not from an editor's impression.