What is meant by work done by a force?

What is meant by work done by a force? When do we call work done to be positive or negative? In a game of “tug of war” state the type of work done by the winning and the losing teams.

If a force applied on a body moves it or displaces it to some extent, then we can say that the work is done by the force.
If the direction of force and displacement is same, i.e. the angle between force and displacement is 0°, then the work done will be positive.
If the force and displacement are opposite to each other, i.e. the angle between force and displacement is 180°, then work done will be negative.
In the game of “tug of war” work done by the winning team is positive and the work done by the losing team is negative.