Dear Word Detective: I just used the expression “deader than a doornail.” Why is a doornail dead? — Dick Stacy.
Beats me. Too many bacon cheeseburgers? Texting while driving? Mowing the lawn during a thunderstorm? I almost lost an in-law that way a few years ago. Heck, I almost lost myself installing a window air-conditioner under similar circumstances a couple of years later. Boom. Zap. And I haven’t been able to balance my checkbook ever since.
Of course, doornails aren’t alive in the normal sense anyway. The Oxford English Dictionary (OED) defines “door-nail” as “A large-headed nail, with which doors were formerly studded for strength, protection, or ornamentation.” The term “door-nail” first appeared in print in the 14th century, long before home alarm systems, when having a thick, strong door was your best defense against the unpleasantness outside getting in.
“Dead as a doornail” (or, I suppose, “deader than a doornail”) means, of course, utterly and completely dead, whether figuratively (“The Congo treaty may now be regarded as being as dead as a doornail,” 1884) or literally defunct in the Monty Python Dead Parrot sense (“This parrot is no more! It has ceased to be. It’s expired and gone to meet its maker. This is a late parrot. It’s a stiff. Bereft of life, it rests in peace. If you hadn’t nailed it to the perch it would be pushing up the daisies. It’s rung down the curtain and joined the choir invisible. This is an ex-parrot.”).
Interestingly, the earliest use of “dead as a doornail” found in print (so far) is from 1362, just twelve years after “doornail” itself first appeared, and Shakespeare used it in several of his plays. The next few centuries saw the rise of several other “dead as” phrases (including “dead as a dodo,” “dead as mutton,” and “dead as a herring,” meaning smoked herring), but none proved as popular as “dead as a doornail.” Of course, the “doornail” version had a linguistic advantage over the “herring” and “mutton” phrases, being alliterative with two words beginning with hard consonants, the pop-speak equivalent of being given three out of five winning lottery numbers as a head start.
But “dead as a dodo” sported the same consonants, so many people have wondered over the years if there might be (or have been) some actual logic to “dead as a doornail” that would explain its popularity. Two theories have thus been offered to explain the phrase. One is that the “doornail” in this case is actually a very large-headed nail (or metal plate) affixed to the outside of the door on which the swinging door-knocker strikes. In this theory, the “doornail” would be dead because it had been struck so often. Unfortunately, there is no evidence that the plate beneath such door-knockers was ever known as a “doornail,” so this theory is unlikely to be true.
The other theory makes a bit more sense. It is said that when doors were constructed in days of yore, carpenters used long, stout nails to hold them firmly together (which, as we’ve seen from the OED definition of “doornail,” is true). This theory holds that the nails were long enough to be driven entirely through the door to the interior side, where they were bent flat (or “cinched,” as carpenters say) to ensure that they would never work loose (and could not be removed from the outside). The nails, goes this theory, would then be “dead” in the sense that they would not move and could never be re-used. This theory actually makes perfect sense and may well explain the original logic of the phrase. It’s not a slam-dunk certainty, but, given that we’re talking about the 14th century, it makes a lot more sense than most theories about phrases that old.