In physics, "work" is when a force applied to an object moves the object in the same direction as the force. If someone pushes against a wall, no work is done on the wall because it does not move. However, depressing a letter on a computer keyboard requires work.
In physics, the equation for work is W = f x d. This means work equals force times distance. Distance is typically measured in meters. The force is a measure of the mass of an object times its change in motion, or acceleration. This is measured in newtons. The amount of work done is measured in joules.