Inverse variation describes a relationship between two variables where one variable increases while the other decreases. This means that the product of the two variables remains constant. For example, if x increases, then y must decrease to keep the equation xy = k true, where k is a constant. In practical terms, inverse variation can be seen in scenarios like speed and travel time. If a car travels faster (increased speed), the time it takes to reach a destination (decreased time) will be shorter, illustrating how these two quantities are inversely related.