Isn’t that the type of horse drawn cab that Cramer took care of while the original driver was on vacation? That would be NYC in the US of A.He fed rusty too much bean-o, causing a gaseous eruption, an abbreviated ride for George’s future in-laws, and a calamity of marbled rye restoration.
Or was that a “handsome cab”? 
One thing I’d like to point out is that knowing the meaning of a word and knowing a preexisting definition for it aren’t quite the same thing, nor is being able to come up with a good definition. We all know what a table (furniture) is, but asking people to define one can be an interesting exercise.
No, you can’t include in the definition “has four legs”, as it excludes all those tables which don’t; on the other hand, it’s also relatively easy to end up with a definition that would include beds.
SOME people do, yes. But a lot of people hardly read at all, and of the ones who do, a significant percentage only read popular modern authors. I don’t know what percentage read the classics, but I’m pretty sure it’s a lot lower than you think.
I still think a large number of people still read Arthur Conan Doyle’s Sherlock Holmes stories, especially young boys. The meaning of “hansom” is clear from context. However, I agree that a spoken distinction could be easily misheard.
Calumny, not so much. I can’t think of any popular literature in which the term appears. Perhaps To Kill a Mockingbird?
Do none of the writers Learjeff mentioned count? How about H. L. Mencken?
Those authors are all very well and good (and Mencken’s book is indeed amusing), but the OP wants to know the percentage of people who “know” the definition of the two example words–not how often those words appear in older texts. It’s not the same thing. As has been pointed out above, it’s not exactly clear what the OP (who hasn’t yet elaborated), means by “know a definition,” but in any case that would be a more productive cognitive facility than simply reading a book could establish.
Thanks! I knew about Google Ngram, but hadn’t noticed dictionary.com’s difficulty index. I tried to find more information on the calculation of the difficulty index, but came up short. I actually didn’t know that accusations of calumny were still popular in England, and my wife claimed that hansoms show up so often in period books and TV shows that more people would recognize the word. I do appreciate everyone’s attempts at answers, and for the record, I didn’t even recognize that hansom was a word until I was playing some word game with my wife.
Those works are certainly well-known, but I’m not sure they are widely read. The works GB Shaw, Conrad, Dickens, Dumas and RL Stephenson all seem far better known from their movie or stage versions than from the actual writings. Stage versions often don’t use the same words, and even if they do, people tend not to learn words from hearing single usages like that.
I can’t prove it, but I suspect that relatively few people have actually read *any *Shaw, Conrad, Dumas or RL Stephenson. Less than one in 500 I would guess. Dickens is certainly more popular, but if the work in question is “The Pickwick Papers” then imagine less than one in a thousand have read it.
As noted, the word hansom is used regularly in the Sherlock Holmes stories, which in my experience most “readers” have had a crack at it as children. The fact that a hansom plays a pivotal at the very beginning of the very first adventure helps the level of exposure. A hansom is also an important plot point in “The Magician’s Nephew”. While this isn’t the most widely read of the Narnia novels, the exposure from this source is huge.
As I said, I can’t prove it but I would imagine that far more people have read Sherlock Holmes or the Magician’s Nephew than have read Shaw, Conrad, Dumas, RL Stephenson or “The Pickwick Papers”.
They’re both obscure, but I would have thought hansom more obscure – maybe because the thing it represents doesn’t exist any more.
Both are words I understand in context. I might possibly use calumny in writing. Probably not in speach. I can’t imagine wanting to use hansom.
From nyctourist.com.
Nitpick: Carriages of the type seen in Central Park are not, in fact, “traditionally called ‘Hansom Cabs’”. A Hansom (named after the designer, Joseph Hansom) is a two-wheeled carriage with a compartment for passengers which is either fully enclosed or, more usually, open to the front only. The driver sits outside, above and behind the compartment. The carriages you see in Central Park are barouches.
Damn those New York liars!
I know it because of being a Catholic kid in the 1950s. We knew the names of lots of sins.
Whenever I think of hansoms, I remember this story. An upper class patron who was leaving London’s Savoy Hotel mistakenly thought that lyricist William Gilbert (of Gilbert & Sullivan fame) was a doorman, this is what is said to have unfolded:
“Call me a cab, sir.”
“Certainly sir. You’re a four-wheeler.” [Another type of cab popular at the time.]
“How dare you, sir!”
“Well, you asked me to call you a cab and I certainly couldn’t call you hansom.”
That might have been an example of calumny. 
Reviving this to mention that Slate wants to revive calumny as a common word. They wrote a full article singing its praises.
Right. I also recognized “hansom” as a kind of carriage, but am not exactly sure how it differs from a cabriolet or stagecoach. In any event, I could likely “pass” a reading comprehension test that used “hansom”.
Trying to define what it means to “know” the definition to a particular word is more complex than it seems on its surface. If someone knows that “oxygen” is a gaseous element that is essential to human life but can’t remember how many protons and electrons it has, can they really be said to “know” the definition of oxygen? If someone knows that Warren Harding was a president of the USA but can’t remember the year in which he was elected, what party he belonged to, and how many children he had, do they really know who Warren Harding was?
How about Shakespeare?
“Be thou as chaste as ice, as pure as snow, thou shalt not escape calumny. Get thee to a nunnery, go.” (Hamlet)
nolonger lurking, I just want to say that you and your wife are my new heroes. I would love to sit around the breakfast table having conversations like that.
Read enough English historical fiction and you’ll learn that the Brits are always committing calumnies against each other between trips to the Royal Albert Hall in their hansom cabs
I only know hansom cabs from reading Sherlock Holmes stories. I knew that word on sight.
I did now know “calumny” except that I knew it was something “bad”. I probably read it in context in some story so it was in the back of my mind.
These are definitely obscure but to me hansom less so.
(My favorite obscure word ever is “defenestration”.)
