Idioms can become such a routine part of the language that we often don’t step back to wonder where these expressions came from. They often have wonderful histories.

To give you some examples, let’s think about a few idioms that involve hats.

We’ll start with “a drop of a hat.”

There are competing theories about where this idiom originates. And I’m sorry to say, I don’t have a clear answer for you in terms of where precisely “at the drop of a hat” comes from.

One common theory is that perhaps on the American frontier people started fighting at the drop of a hat. In other words, dropping a hat was how you signaled the beginning of a fight.

Nice theory. But we don’t have a lot of evidence for it.

Michael Quinion, on the terrific website World Wide Words, offers what may be the earliest example of the idiom, dating back to 1837, where the phrase “at the drop of the hat” is synonymous with “in the twinkling of an eye” (as well as “at the crook of a finger”). It stands for something that would happen quickly – in the case of this 1837 example, agreement.

We get other examples of people who might get married at the drop of a hat. The phrase becomes much more popular in the second half of the 20th century, but we’re not quite sure why we’re talking about a hat.

Next, let’s talk about “hat trick.”

At this point, a hat trick is associated with ice hockey in the U.S. But that’s not actually where it comes from. It also does not come from magic tricks, although that would be kind of great, or from street performers. (As a relevant aside, the expression “pass the hat” does come from street performers.)

Hat trick comes from the sport of cricket.

The story goes that in cricket, if a bowler took three wickets with three successive balls, he was entitled to get a new hat from his club. So that’s the source of the three-ness, and we now see hat trick associated with three goals in ice hockey or, outside of hockey, with three wins or three successes.

And finally, let’s consider the history of “mad as a hatter.”

There’s good reason so many of us associate the expression “mad as a hatter” with Lewis Carroll and his book Alice’s Adventures in Wonderland. There is a very famous hatter in that book, and he attends a “mad tea party” along with the March Hare. Lewis Carroll never specifically refers to him as the mad hatter, although the Cheshire Cat does refer to him as mad.

The expression “mad as a hatter,” though, has a much sadder history. And it predates Lewis Carroll’s book. It goes back to the early 19th century, and it comes from the process by which people made felt hats.

Often as part of the process, the hatter needed to brush the fur for the hats with a substance that contained mercury. As a result, some of the hatters suffered from mercury poisoning, which, among other effects, can result in loss of memory and slurred speech, which could make the hatter seem a little bit mad.

I’d like to close by saying, “Hats off!” to the people out there who already knew the history of that expression.

This video appears courtesy of LSA Today. A version of this material also appeared on “That’s What They Say” on Michigan Radio.