Abbreviations in poker tracker

[jamazon]

Hi,

I am looking at poker tracker and do not understand what some of the abbreviations mean (where can I go to learn about this?). Near the bottom, it said "player actions" with options such as bet/raised/check-raised, what does WSD% means (winning at showdown %?)? Also, what does the percentage at each row means? The percentage of winning a hand on that street?

Thanks.