Not depictable graphically as a straight line; not changing by a constant amount for each unit of time, distance, or other independent variable. Opposite of linear.

Containing variables of greater than the first degree; -- of an equation. Opposite of linear.

Represented by equations containing variables of greater than the first degree; -- of physical processes or relationships. Opposite of linear.

Literally, not linear.

Not having a one-to-one direct proportional relationship between input and output.

A product or process that exhibits an uneven distribution, or wide variations in terms of quantity and timing.

A relationship between numerical quantities is called nonlinear if there is not a constant proportion relating changes in one quantity to changes in the other. Exponential growth, as occurs when compounding interest over time, is an example of a nonlinear relationship.