Offensive Rating – The number of points scored per 100 possessions by a team. For a player, it is the number of points per 100 possessions that the team scores while that individual is on the court.
Defensive Rating – The number of points allowed per 100 possessions by a team. For a player, it is the number of points per 100 possessions that the team allows while that individual is on the court.
Net Rating – Nat Rating is the difference in a player or team’s Offensive and Defensive Rating. The formula is: Offensive Rating – Defensive Rating.
Player Impact Estimate – PIE is an estimate of a player’s or team’s contributions and impact on a game. PIE shows what % of game events did that player or team achieve.
Rebound Percentage – The percentage of total rebounds a player obtains while on the court.
Assist Percentage – Assist Percentage is the percent of teammate’s field goals that the player assisted.
TS% – True Shooting Percentage. Instead of relying on standard shooting percentage, this stat takes into account free throws as well as the additional point gained from three-point range, weighting each outcome appropriately. True Shooting Percentage gives a more accurate picture of offensive efficiency.
EFG% – Effective Field Goal Percentage is a field goal percentage that is adjusted for made 3 pointers being 1.5 times more valuable than a 2 point shot.
PER – Player Efficiency Rating. PER attempts to determine a player’s productivity on a per-minute basis. The fallback of PER is a lack of reliable defensive statistics to input beyond steals and blocked shots.
Win Shares – Win Shares is a combination of defensive win shares and offensive win shares, which are generated through a formula which tracks marginal points. The purpose of Win Shares is to estimate how much a player contributed to his team’s win total.
The leaderboard for the majority of these stats can be at NBA.com.