A practical effect is a special effect produced physically, without computer-generated imagery or other post production techniques for actual live filming purposes.
In some contexts, "special effect" is used as a synonym of "practical effect", in contrast to "visual effects" which are created in post-production through photographic manipulation or computer generation. Many of the staples of action movies are practical effects. Gunfire, bullet wounds, rain, wind, fire, and explosions can all be produced on a movie set by someone skilled in practical effects.
Non-human characters and creatures produced with make-up, prosthetics, masks, and puppets – in contrast to computer-generated images – are also examples of practical effects.