No, yrn means 'yarn round needle' which indicates that you wrap it all the way around so you end up in front. None of the terms mean to wrap the yarn backwards, if a pattern has you do that they do call it 'yo backwards' or describe it as such.
As said before, British terms describe how you wrap the yarn between different stitches. The other one is yon - yarn over needle - and is when you go from a purl to a knit - you just loosely lay the yarn over the top of the needle to the back.
sue- knitting heretic