Keep it under your hat
I am rather partial to wearing a hat, a Panama on the rare occasions it gets hot enough to warrant it and a cap or a trilby in winter. After all, there is an urban myth, propagated by the US army survival manual, that you lose up to 40 to 45 per cent of your body heat through your head. Scientists have poured cold water on this but you can’t be too careful, I say. Anyway, our idiom means to keep something secret or quiet; store it away.
The figurative sense of the phrase is easy to understand. After all, what is underneath your titfer is your head and this is where you keep your thoughts and secrets. The earliest printed example of a variant of the phrase, without the verb to keep, appeared in William Thackeray’s The History of Pendennis, published in 1848. There the author wrote, “Thus, oh friendly readers, we see how every man in the world has his own private griefs and business…Ah sir, a distinct universe walks about under your hat and under mine”. In 1881, in W B Westall’s The Old Factory, a Lancashire Story, we find our phrase for possibly the first time; “that he could not afford to keep a wife, that he preferred to keep his family under his hat or that he could not find a lass to suit him”.
The phrase seems to have crossed the pond because it appeared in doubtless popular Gleanings in Bee Culture of 15th October 1892. Interestingly, though, the sense is of secrecy as in Westall’s usage rather than thoughts, as in Thackeray’s. “..tell us where you know of a producer who is engaged in the mixing business, and we will keep it under our hat if you say so”. The wonderful P G Wodehouse in the Inimitable Jeeves of 1923 reverted to the original sense; “it made such a hit with her when she found that I loved her for herself alone, despite her humble station, that she kept it under her hat”.
Some etymologists claim that the phrase is American in origin and that refers to Abraham Lincoln’s rather quaint habit of storing important papers in his rather capacious stove-pipe hat, what he termed his office. But this can’t be the case, charming as the theory may be, because Thackeray’s usage predates him and there is no reason to suppose that it is American in origin.
Another theory is that it is a reference to the custom deployed by English archers of keeping their spare bow strings secure and dry by placing them under their caps. The ceremonial sword bearer of the Lord Mayor of London kept the key to his master’s seal of office in a special pocket in his titfer. I’m sure may things have kept under a hat over the course of the centuries, nits and dandruff not included, so it does not seem necessary to try to select one of these more exotic practices as the origin of our idiom. What is undeniably true is that in all circumstances when a hat is worn what is under it is your head and within your skull, your brain. This simple truth matches Thackeray’s usage.
Of course, if I find a more compelling explanation, rest assured, I will not keep it under my hat.