What does O mean in old patterns?

I’m knitting a doily from an old pattern, and I’m flummoxed by something called O. There’s no indication on the pattern as to what it means.

I[SIZE=2]'ve just started, so I have 6 stitches on each dpn. The next line reads: * K 2, O, k 1, O. Repeat from * around (10 sts on each needle).

So it’s definitely an increase, but not just a yarn over, because in order to get 10 stitches from 6 with that line, I need a double increase, right?

Maybe a double YO, and knit into both on the next round? But why would that just be called O? :??
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It’s just a regular YO. The repeat uses 3 sts and adds 2, so you do [SIZE=2]K2, O, k1, O[/SIZE] twice, and that will give you 10 sts.

Oh! As usual, I was overthinking (and not counting)… Thanks!

Some days it’s hard to count to 3… we’ve all been there.