nonlinear

nonlinear

adj.
  1. 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. (Math.)
  2. Containing variables of greater than the first degree; -- of an equation. Opposite of linear. (Math.)
  3. Represented by equations containing variables of greater than the first degree; -- of physical processes or relationships. Opposite of linear. (Physics)