Possession:

Two teams in any given game are essentially limited to the same number of possessions. It means winning team will have more points per possession than loosing team. A possession ends (by nbastuffer.com):
- by making a field goal attempt;
- by missing a shot and not getting the offensive rebound;
- by turning the ball over;
- by going to the line for two or three shots and either making the last shot or not getting the rebound of a missed last shot.

Traditional stats:

PIR - Performance Index Rating (PTS + (2FGM - 2FGA) + (3FGM - 3FGA) + (FTM - FTA) + OR + DR + AS + ST - TO + (BlFv - BlAg) + (FlCm - FlRv))

PPG - Points Per Game

RPG - Rebounds Per Game

APG - Assists Per Game

SPG - Steals Per Game

BPG - Blocks Per Game

+/- - Plus/Minus Per Game. Calculations use free throws correction for subs during or before free throws

MPG - Minutes Per Game

Shooting stats:

2P% - Two points shots percentage 2FGM/2FGA

3P% - Three points shots percentage 3FGM/3FGA

FT% - Free throws percentage FTM/FTA

EFG% - Effective field goals percentage, includes two points shots and three points shots (FGM + 0.5 * 3PM) / FGA

TS% - True shooting percentage PTS / (FGA + 0.44 * FTA)

Advanced stats:

USG% - Usage Percentage. Percentage of possessions finished by player from team's possessions number when player is on court

Team Pace - Number of possessions per 40 minutes

Player Pace - Number of possessions per 40 minutes when player on the court

Pts/Pos - Number of points scored per possession. Usually winning team has higher Pts/Pos rate then losing team

To/Pos - Number of turnovers per possession.

OffRtg - Offensive rating. Number of points scored per 100 possessions by current team. For player - number of points scored per 100 possessions when player is on court.

DefRtg - Defensive rating. Number of points scored per 100 possessions by opposite team. For player - number of points per 100 possessions scored by opposite team when player is on court./p>

NetRtg - (OffRtg - DefRtg)

TReb% - Total rebounds percentage. Percentage of player's total rebounds from available rebounds when player is on court

DReb% - Defensive rebounds percentage. Percentage of player's defensive rebounds from available rebounds when player is on court

OReb% - Offensive rebounds percentage. Percentage of player's offensive rebounds from available rebounds when player is on court

PIE - Player Impact Estimate. PIE = PTS + FGM + FTM - FGA - FTA + DREB + (.5 * OREB) + AST + STL + (.5 * BLK) - PF - TO) / (GmPTS + GmFGM + GmFTM - GmFGA - GmFTA + GmDREB + (.5 * GmOREB) + GmAST + GmSTL + (.5 * GmBLK) - GmPF - GmTO)