Is It “Prussik” or “Prusik”? And Should It Be Capitalized?

The prussik/prusik is an extremely useful knot used for ascending a fixed rope, taking the load off of a rope, and backing up a rappel, among other things. But how is it spelled? Is it prussik or prusik? I know I’ve seen it spelled both ways, and you probably have too. In fact, a search for each of those terms on Mountain Project pulls up multiple pages for each.

The answer is that it should be prusik. The inventor of the knot is one Karl Prusik, and his name was spelled with just the one S. I think the confusion comes with the way it’s pronounced: pruh-sick (the pruh rhymes with duh), not prew-sick.

So that leads us to the next question: Should it be prusik or Prusik? I just took a look at 8 instructional climbing books in my collection to see what they do. Four of them have a lowercase P. Three of them have the capitalized P. And one of them has a lowercase P but spells it with the double SS. So it seems like the lowercase P is the new standard. The books that capitalize it tend to be the older ones.

So in the prussik/prusik/Prussik/Prusik battle, I declare prusik to be the winner.