- Not in a straight line.
- Mathematics Occurring as a result of an operation that is not linear.
- Mathematics Containing a variable with an exponent other than one. Used of an equation.
- Of or relating to a system of equations whose effects are not proportional to their causes. Such a set of equations can be chaotic.
- Of or relating to a device whose behavior is described by a set of nonlinear equations and whose output is not proportional to its input.
- Of or relating to the output of such a device.