Gamerscore

A Gamerpoint is an award given in a numerical value shown on your gamertag. You attain gamerpoints after completing special tasks in a game, otherwise known as achievements. In some games, gaining a certain amount of gamerpoints unlocks something in the game, such as armor or new weapons, or gaining a certain number of gamerpoints can also gain achievements in some games. While most games have 1000 gamerpoints in total, some games (eg. Xbox Live Arcade games) have far less than 1000 gamerpoints. Also, some games are not shipped with 1000 gamerpoints, but offer achievements as downloadable content. It is also called a "Gamerscore" by most people. Normally a game has 1000 gamerpoints but if an expansion pack is released more can be added on.

Note: These are not to be confused with "Microsoft Points", a stored-value system used for purchasing content on Xbox Live.