Online games are games usually on the internet to entertain people. They are usually games where you have to control a certain person or object to do something. Most online games use the arrow keys, space bar and other keyboard characters to control the person or object. These can be referred to as mini games.
The other type of online games is a larger network where players log in with a user name and the game lets them interact with other 'players' and develop statistics, high scores, earn money, awards, badges or stamps. The games tend to be based on animals or virtual worlds.