Australian Yarn translated to American? HELP!

I’m about to attempt to knit a cardi from an Australian site. They say to use “8-ply” yarn…what does that translate to? Sport weight, maybe?

The cardi is to be knit on 4mm/US6 needles and at a “tension of 21 sts and 33 rows to 10cm over patt”.

Yeah, I think that would be more like DK weight, but some sport weights are heavy enough. Look at this explanation - http://yarnforward.com/tension.html

I think that would be more like DK weight, but some sport weights are heavy enough. Look at this explanation - http://yarnforward.com/tension.html