99% of patterns (be they in a book, in a zine, in a pamphet, on line, (free or download paid for PDF) come with a LEGEND.
The LEGEND explains what is meant by the abreviations used in patterns.
sometimes, the legend is located in a separate place (Knitty.ocm for one, has a Legends page, and require every one who submits a pattern to use their abreviations. You have to look for the legend.. but its not hard to find.--and it is NOT generally included in the pattern directions --it is a separate page, stored in a separate location.
Most print magazines have legends just before all the pattern details/or with info about the yarns.
You should learn to look for a legend (and make a copy of it!) when you copy the pattern--(or download it when you down load a pattern)
there are some 'generally agreed on" abreviations.. but there different terms commonly used in US vs. UK (and places like the commonwealths countries often pick and chose--using a mix of US and UK terms!)
Yfwd is MOST COMMONLY equal to YO. but sometimes in a slip/mosaic pattern, Yfwd or Ybk (yarn back) refers to the position of the yarn..
In Linen stitch (for 1) you always slip stitches with the Yarn on the front of the work (on the KNIT side, you bring the yarn forward (as if to purl)before slipping the stitch, and on the purl side you bring the yarn back (as if to knit) before slipping the stitch.
since your stitch pattern doesn't have slipped stitches, its a good guess Yfwd =YO.
but the only way to know for certain is to consult the legend--and learn what the designer meant..