What does W.O.N. mean?

I just downloaded a hair snood pattern from 1944 and the first row reads K. 2tog., W.O.N. (thus making a st.) can anyone explain this abbreviation. Thank you:knitting:

According to Vintage Purls ( http://www.vintagepurls.net.nz/abbreviations.html ) , it is used to make a st in between a purl and a knit st…so after you are done your purl, you would bring the yarn over the needle to the back, ready for the next knit st.


Wool Over Needle—a YO