Much better than our basement smells when it floods every Spring.

Dear Word Detective: I notice that the top-rated word at your “My Favorite Word” website is currently “petrichor,” which I have never encountered before. It’s not in any online dictionary I’ve been able to find. Is it a real word, and where does it come from? — D. Bailey.

Yes, “petrichor” is a real word, and a very cool one at that. But before we get too far, I should probably explain that I started “My Favorite Word” (www.myfavoriteword.com) a while back as a sort of adjunct to our Word Detective website. At My Favorite Word, you can, as hundreds of folks already have, submit your own favorite word (and, more importantly, explain why you like it), as well as read and rate the favorites of other visitors. I’ve been fascinated by the response from readers, who have sent in words ranging from “autumnal” (“Autumn is my favorite season, mists, mellow fruitfulness, smoke, ripening apples, reddening leaves, the whole atmosphere of battening down snugly for winter”) to “sequoia” explained with a hint of Yoda (“Beautiful, it is. And it’s the shortest word in the English language to use all the vowels!”). We even apparently have a reader whose favorite word is “squish.”

“Petrichor” is an intriguing word, not only for its inherent beauty but because, as the submitter put it, “How many words are there out there for specific scents?” According to the Oxford English Dictionary, “petrichor” is “A pleasant, distinctive smell frequently accompanying the first rain after a long period of warm, dry weather in certain regions.” If you’ve ever been captivated by the smell of a sudden summer shower, “petrichor” is your word.

Although “petrichor” sounds quite poetic and ancient, it’s actually of fairly recent vintage, having been coined in the pages of the scientific journal Nature in 1964. Evidently, organic compounds in the air, most emitted by plants, fall to earth and combine over time to produce an oily resin, essentially a complex perfume, in the dry ground. The globules of this perfume are then liberated and spread by falling rain, producing that distinctive smell. “Petrichor” is thus much more than just the smell of wet dirt.

In naming this compound and its wonderful scent, the scientists in Nature reached back to Latin and Greek. “Petro” (from the Latin “petra”) is a combining form meaning “stone” (also found in “petroleum” and “petrified”), while “ichor,” from Greek, means “essential fluid” or, in a poetic sense, “essence.” So “petrichor” means “essence of stone,” which may not be scientifically precise but strikes me as the perfect name for that smell.

Not my job.

Dear Word Detective: My sister and I have a bet regarding the phrase “passing the buck.” I think it refers to the early 19th century Kansas frontiers when it was common to pass around large plates of venison. She insists that the phrase originated when the term “greenbacks” was shortened to “backs” and then “bucks,” which makes even less sense. We clearly need your help. — Daniel Jorgenson.

Large plates of venison? I’ll pass, thanks (and yes, I’ve tried venison, many years ago). For some reason, that theory reminds me of a Mike Williams cartoon from Punch we used to have taped to our refrigerator, which showed a bunch of bears lounging around in their cave. One is peering into the refrigerator and saying, “Well, that’s the last of the Mohicans … there’s a little bit of Sioux if anyone’s interested.” (Cartoonist’s website is here.)

To “pass the buck” today means to evade responsibility by shifting it to another person. The term comes from the game of poker as played in 19th century America, where players took turns acting as dealer. To keep track, a marker known as the “buck,” often a knife with a handle made of buck horn, was placed on the table in front of the dealer, and passed to the next player before each round (“I reckon I can’t call that hand. Ante and pass the buck,” Mark Twain, 1872). By the early 20th century, “pass the buck” had spread from meaning “to transfer responsibility from one poker player to another” to meaning “to shift responsibility for anything to another person,” the sense we use today.

Although “buck passing” is a core survival skill for anyone working in a large organization (especially a government bureaucracy), being on the receiving end of “Oh no, you need to talk to the Office of Non-Euclidean Contingencies, Room 647 in Building B-104″ can be very annoying. It’s even more annoying when the bureaucrat saying that is a politician you voted into office. So in 1949, when President Harry Truman put a sign on his Oval Office desk announcing that “The buck stops here,” he meant that he would accept ultimate responsibility for the actions of his government. Whether that promise was kept is, of course, a matter of opinion, but the slogan was an instant hit and “the buck stops here” is still invoked dozens of times in every presidential race.

As for your next question (I’m psychic), why a dollar is known as a “buck,” the answer is uncertain. Some say that it comes from the use of deer hides (“buckskins”) as currency worth one dollar in early America, but buckskins were worth more than that and “buck” meaning “dollar” didn’t become popular until the 20th century. It’s more likely, in my opinion, that “buck” in this sense is derived from the slang “sawbuck,” meaning a ten-dollar bill. The Roman numeral “X” (meaning ten) was emblazoned on early ten-dollar bills, and resembled a “sawbuck” (from the Dutch “zaag-bok”), or what today we call a “sawhorse.” Since a “sawbuck” was worth ten dollars, people may have assumed (especially after the “X” was removed from the bills) that “saw” had something to do with “ten,” so just one dollar must be a “buck.” That’s just my own theory, of course, but I like it.