I have a bit of a gripe about sock yarn. I'm quite literal about what sock yarn is, to me it means "yarn suitable for sock knitting" which is why on the website I've always distinguished between sock yarn and fingering yarn. (I know, I know, I'm British but use "fingering" instead of "4 ply" but that opens up another discussion and besides, it means I get to say I have a "Fingering Floor" in the studio and laugh like a juvenile).
The terms "sock yarn" and "fingering" are often interchangeable and this comes with problems. As we've all evolved to read the internet in numbers (cheers Buzzfeed), I'll write a numerical list.
1. Just because a yarn is in the region of 350 - 425 metres, it doesn't mean it is suitable for sock knitting.
2. Merino, beautifully squishy, takes dye like a dream, NEEDS nylon blended in for sock knitting. Merino has a short staple length which makes it liable to pill when you look at it and therefore not that strong.
3. Single ply yarns being used to knit socks. No, no, no. You need a plied yarn for strength, ideally a nice tight twist. Also, single ply yarns stretch like mad so you'll get soft clown socks that will make you trip over and I'm the type of person who laughs at that kind of thing.
4. Yarns made from long staple length fibres, such as Bluefaced Leicester and Mohair are the dogs' bollocks for sock knitting. They are tough, do not pill very easily and they do not need to have nylon blended in, just a good twist in the ply.
5. Machine washable yarns have their uses. Easy care, bonus.
6. Although non-superwash yarns are handy if you don't mind hand washing. You'll find the wool will felt in high friction places like the heel and sole which makes an even stronger sock. Also this means nobody can steal your socks to wear because they will have moulded to the shape of your foot.
Now obviously I'm telling you all this because my Sock Yarn (with nylon) section in the shop is quite barren at the moment (more is coming) but I do have an alternative for a non-nylon sock yarn which fits the bill; The Bluefaced Baron Fingering which is 100% high twist superwash Bluefaced Leicester and there is some of that in stock.
I'm also telling you because I feel quite sad at hearing so many stories from people who have knitted socks with unsuitable yarn because it's been sold to them as "sock yarn".
There are times when being very literal is a benefit. Not often though, but this is one of them.