I have talked before about how people I talk to look upon swatching. How they try to get out of it and how gauge is not a universal thing. There is another thing that is not universal: plying. I sometimes meet knitters who ask for 2-ply yarn for a certain pattern. The problem is that 2-ply yarn could be anything. It can be lace weight and it can be bulky. I know that there are older patterns that state that you need 2-ply yarn and that’s it, which makes me think that once there actually was a universal measure for 2-ply yarn. But, there isn’t anymore. Therefore you have to play detective to determine what yarn to use when it comes to those patterns but that’s not as easy as it sounds.
I’m guessing 2-ply yarn in older patterns means something around fingering weight, if you follow the logic that the more plied a yarn is, the heavier the weight. It’s a great logic except that it doesn’t work. I know of bulky yarn in single ply and of lace weight in 4 ply and everything is just a mess.
So let’s once and for all state the fact here: that a yarn is 2-ply says nothing of the yarn weight.