Did you mean "responding variable"? If so, the responding variable, or dependent variable, is the variable that reacts based on fluctuations in the manipulative variable. The manipulative variable, sometimes referred to as the independent variable, is the variable that is purposely altered in order to measure changes in the responding, or dependent variable.
In other words, the responding variable is dependent on the manipulative variable. The responding variable is the one you measure in order to observe the results of changes in the manipulative variable.
So, if you're changing the growth rate of a type of plant in different types of environments: sunlight, artificial light, and shade, for example -- then the environment that you alter is the manipulative (independent variable) and the growth rate of the plant is the responding (dependent variable).