In sailing, what does a knot measure?

I knew the answer but not the explanation Thanks for that.

It's nice to get these interesting explanations. I love this game.

it also is a measurement of wind speed!

sailing...by christopher cross

As previously stated, knots also measure wind. These types of questions are frustrating when you answer correctly but get it wrong

I did knot know that :-)

I did knot know this was how it was invented.