What does PS mean in shoes?

Excuse me, could you please clarify for me the meaning of the abbreviation "PS" when it's used in the context of shoes? I've seen it mentioned a few times but I'm not entirely sure what it stands for or what it signifies in the world of footwear. I'm curious to know if it's a specific style, a sizing indicator, or something else entirely. Thank you in advance for shedding some light on this for me.