What's the meaning of (k2tog, 4 sts) 3 times

I have difficulties on understanding a knitting pattern, in one of the rows:
K2, (k2tog, 4 sts) 3 times, k2tog, k9, (ssk, 4 sts) 3 times, ssk, k2. 45 sts.
what’s the meaning of (k2tog, 4 sts)? How to knit it out?

Welcome to KH!
Interesting. What pattern are you working? Can you give us the name or a link to it?