Is It Duck Tape or Duct Tape?
If you’ve been rolling your eyes at people who say “duck tape” adhesive, prepare some apologies. The durable cloth-backed tape first appeared during World War II, when Johnson & Johnson developed an olive drab version as a handy way for American soldiers to waterproof their ammo cans. According to the company, soldiers dubbed the product “duck tape” because it forced moisture to flee “like water off a duck’s back.”
Troops realized that the tape was good for more than just keeping their powder dry, and after the war, it caught on as an easy and effective way to seal, among other things, heating ducts. Johnson & Johnson even began offering a silver version of the tape specifically for this purpose, giving rise to “duct tape.”
So which is correct? “Duck tape” has the chronological upper hand, but “duct tape” is a more accurate description of the product’s historical use. To make things even more complicated, though, it's no longer used to seal ducts! You could always just hedge your bets the way the leading manufacturer does when it bills itself as “Duck brand duct tape.”