• An element, feature, or factor that is liable to vary or change.

• Anything that can take on differing or varying values.

• A characteristic, number, or quantity that increases or decreases over time, or take different values in different setting/situation.

Some examples of Variables

Production rate, absenteeism rate, & performance, level implementation, maturity, Facebook addiction, productivity, costs, flexibility, growth, profit, satisfaction, service/product quality, lean implementation, etc.