Definition of Linearity:
Property of ordered systems and straight lines, characterized by good behavior, predictability, and simple proportions. It is not a common feature of the natural (real) world and exists mostly in theories. See also nonlinearity.
Situation where a dependent variable has a liner relationship with one or more independent variables and, thus, can be computed as the linear function of the independent variable(s).
Meaning of Linearity & Linearity Definition