I am fresh from silvers sock class and thought I could knit these really simple baby socks but was looking at the pattern and saw this.

HEEL FLAP (worked on 12 sts):
Row 1: [Slip 1 PW, K1] repeat across, turn
Row 2: Slip 1 PW, Purl across, turn

What doe PW mean is at a sock knitting turm?

there's no definition for it anywhere on the pattern?

I'd say it means 'purl wise' - so slip one stitch as if you were going to purl it.

I'd agree with Marilyn. It's before the comma so it's part of the SL1 segment. It fits as far as what do do, too.

I agree that it is slip 1 purlwise. Good luck!