The tape was originally called duck tape, for its water-repelling properties. (Duck ...water ... get it?) And, as the story goes, the fabric used to make the tape was called cotton duck. Soldiers soon discovered that the tape was incredibly useful in repairing just about anything that needed repair, from jeeps to planes to tents to boots. As time went on, "duck" morphed into "duct" because of its use in the postwar building industry to help connect … you guessed it … ductwork for heating and air conditioning.But I still couldn't find a shred of evidence for this, so I asked the J&J librarian, Margaret Gurowitz, what it was based on. Her reply, which arrived after the column went to press, says, essentially, that there is no evidence -- it's just company folklore.
Unfortunately, I don't have any additional information on the transition from "duck" to "duct" tape. ... Because duct tape was invented as a wartime product for the military during World War II, there was no product launch and publicity of the kind that would happen with most products. ... The story about it being originally called "duck" has been passed down verbally here, and it also can be found on the many websites devoted to duct tape. Since it was originally developed as a waterproof tape to keep ammunition cases dry, and it was said to have been made using cotton duck fabric, the story of the origin of its name does make sense.
*Behind a paywall at the Globe, but reproduced here.
**Update: Dammit, Michael Quinion, whose eyes are clearly better than mine, points out that the pub date of this article is not 1938 but 1958. Doesn't affect the conclusion, but puts a serious dent in my satisfaction. However, a 1958 date is evidence of a different sort: The article shows men taping ductwork and describes the tape as silver colored, but does not call it "duct tape" (or "duck tape" either).