Total Shots (Corsi) = All shots directed toward goal. Missed Shots + Blocked Shots + Shots on Target + Goals.
Total Shot Ratio ( TSR% or Corsi%) = Total Shots For/(Total Shots For + Total Shots Against).
Shots on Target Ratio (SoTR) = Shots on Target For/(Shots on Target For + Shots on Target Against).
Goals Ratio (GR%) = Goals For/(Goals For + Goals Against)
Shooting% (Sh%) = Goals For/Shots on Target For
Save% (Sv%) = (Shots on Target Against-Goals Against)/Shots on Target Against or Saves/Shots on Target Against
PDO = Shooting% + Save%. Basically, this is a proxy for good or bad 'luck'. 100% is the average. Above 100% is 'lucky' and below is 'unlucky'. PDO does not stand for anything. It is an online pseudonym of the person who came up with the metric. It regresses toward 100% over time and can be very erratic. Here is an article on PDO.
Total Shot Differential or Net Shots = Total Shots For - Total Shots Against
TSR Relative per 90 (TSR Rel/90 or Corsi Relative) = Total Shot differential of player while on the pitch - Total Shot differential of his team, when player is not on the pitch. Broken down to per 90, it tells us how many shots better/worse the team are when that player is on the pitch. ** Sample size is important here and early season numbers have a lot of noise**
Contribution to Shots For p90 = Total Shots p90 + Key Passes p90
Contribution to Shots % = (Individuals Total Shots + Key Passes)/Total Shots For While Player is on the Pitch
Contribution to Goals % = (Individuals Goals + Assists)/Total Goals For While Player is on the Pitch