Here is the pattern stitch for a vest I plan to make-

Pattern Stitch
Chevron Lace (multiple of 6 sts + 1) Row 1 (RS): K1, yo, ssk, k1, k2tog, yo, k1; rep from across.
Rows 2 and 4: Purl.
Row 3: K1, k1, yo, sk2p, yo, k2; rep from across.
Rep Rows 1–4 for pat.

What do you suppose sk2p stands for? There is not a guide.

Thanks in advance.

slip one, k2tog, pass slipped stitch over

Sk2p = slip 1 stitch, knit 2 stitches together, pass slipped stitch over knit 2 together stitch. 2 stitches decreased.