DK vs Sport Weights

I’d like to know the difference between DK and sport weight yarn. They seem to me very similar? But, since there is a different name, I imagine that there is something different about them.

Dk is thicker, nearly a light worsted weight.

A LYS owner from long ago told me that DK stood for “double knitting” and means that it can go two ways. You can make it work for worsted or sport weight patterns. I’m not real sure of that, but that is what she said. Maybe it meant that at one time and doesn’t anymore. It would be interesting to know the history of the designation “DK”.

I believe that double knitting yarn really comes from it being the same weight as 2 strands of fingering weight which was the most common weight years ago. The thin yarn was doubled to knit warmer, thicker sweaters.

That’s right, it does mean that, and it’s still called that in the UK. In fact I wouldn’t know what DK was if you said it (though I could guess!).