The Force is a term from the Star Wars universe. It is a set of mystical powers that all the Jedi and Sith have. They can do many things with the Force, such as lifting an object up without touching it, shooting lightning out of their hands, choking people and many other things.
The sides of the Force
There are two sides to the Force: the light (or good) side and the dark (or bad) side.
The light side
The light side is used for good things like healing. The people who study and learn the light side of the Force are called Jedi.
The dark side
The dark side of the Force is used by the Sith, the bad guys, in the Star Wars movies. Sith have a lot of anger, fear, hate and aggression. The dark side of the Force gives the bad guys powers that the Jedi, the good guys, do not have. For example, Darth Sidious is able to shoot lightning from his fingers. The dark side can seem stronger but that is just because a person who uses the dark side of the Force does not have to hold anything back, he is not restrained.
Sith Lords
Further reading
Other websites