1. designating or involving an equation whose terms are not of the first degree;
The Collaborative International Dictionary of English v.0.48:
nonlinear \nonlinear\ adj.
1. (Math.) 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
[WordNet 1.5 +PJC]
2. (Math.) Containing variables of greater than the first
degree; -- of an equation. Opposite of linear.
3. (Physics) Represented by equations containing variables of
greater than the first degree; -- of physical processes or
relationships. Opposite of linear.
WordNet (r) 3.0 (2006):
adj 1: designating or involving an equation whose terms are not
of the first degree [ant: additive, linear]
The Jargon File (version 4.4.7, 29 Dec 2003):
1. Behaving in an erratic and unpredictable fashion; unstable. When used to
describe the behavior of a machine or program, it suggests that said
machine or program is being forced to run far outside of design
specifications. This behavior may be induced by unreasonable inputs, or may
be triggered when a more mundane bug sends the computation far off from its
2. When describing the behavior of a person, suggests a tantrum or a flame
. ?When you talk to Bob, don't mention the drug problem or he'll go
nonlinear for hours.? In this context, go nonlinear connotes ?blow up out
of proportion? (proportion connotes linearity).
The Free On-line Dictionary of Computing (30 December 2018):
(Scientific computation) A property of a system whose output
is not proportional to its input. For example, a transistor
has a region of input voltages for which its output voltage is
found by multiplying the input voltage by the gain of the
transistor. Outside this region though, the transistor
behaves non-linearly, meaning that it does not obey this
simple equation. The behaviour of a system containing
non-linear components is thus harder to model and to predict.