A sticky question indeed. In fact, historians and etymologists to date have been unable to determine which name came first – ‘duck tape’ or ‘duct tape’. What we do know though, is that these days it’s quite acceptable to use either name.
The story put forward by Johnson and Johnson was that in the early 1940’s the company was asked by the military to produce a tape that could be used to keep moisture out of ammunition cases. The resulting product was supposedly called ‘duck tape’ by soldiers either because its cloth base was cotton duck, or because of its moisture repelling ability – like”water off a duck’s back”.
A cool story but unfortunately up to this point, historians claim that nobody has been able to find any evidence that it is true.
As for ‘duct tape’ there is also a great degree of uncertainty around when the name started to be used. The most likely scenario is that during the post-war building boom it was discovered that the tape was very effective for sealing ducts and at some point construction workers began referring to it as ‘duct tape’.
Regardless of whether the name ‘duck tape’ was in use prior to this, what is certain is that this name definitely became more commonly used after Manco trademarked its Duck Tape brand in the 1980’s.
So while nobody really knows which name came first, these days it’s quite okay to use either.