What is editing?

Editing is what brings a movie to life, editing is used to combine video clips together, combining effects and sound to these video clips let it be a filter such as black and white or a soundtrack or a sound effect to really bring the movie to life. You can also cut video clips at certain areas and combine them to others, speed or slow down. These are only a sample of what editing is used for but if I wore to tell you everything you can do then we'd be here for a while X_X