Second-order may refer to:
Mathematics
*
Second order approximation
In science, engineering, and other quantitative disciplines, order of approximation refers to formal or informal expressions for how accurate an approximation is.
Usage in science and engineering
In formal expressions, the English_numerals#Ord ...
, an approximation that includes quadratic terms
*
Second-order arithmetic
In mathematical logic, second-order arithmetic is a collection of axiomatic systems that formalize the natural numbers and their subsets. It is an alternative to axiomatic set theory as a foundation of mathematics, foundation for much, but not all, ...
, an axiomatization allowing quantification of sets of numbers
*
Second-order differential equation, a differential equation in which the highest derivative is the second
*
Second-order logic
In logic and mathematics, second-order logic is an extension of first-order logic, which itself is an extension of propositional logic. Second-order logic is in turn extended by higher-order logic and type theory.
First-order logic quantifies on ...
, an extension of predicate logic
* Second-order perturbation, in
perturbation theory
In mathematics and applied mathematics, perturbation theory comprises methods for finding an approximate solution to a problem, by starting from the exact solution of a related, simpler problem. A critical feature of the technique is a middle ...
Science and technology
*
Second-order cybernetics
Second-order cybernetics, also known as the cybernetics of cybernetics, is the recursive application of cybernetics to itself and the reflexive practice of cybernetics according to such a critique. It is cybernetics where "the role of the observer ...
, the recursive application of cybernetics to itself and the reflexive practice of cybernetics according to this critique.
*
Second-order fluid
Second-order may refer to:
Mathematics
* Second order approximation, an approximation that includes quadratic terms
* Second-order arithmetic, an axiomatization allowing quantification of sets of numbers
* Second-order differential equation, a di ...
, an extension of fluid dynamics
*
Second order Fresnel lens, a size of lighthouse lens
*
Second-order reaction, a reaction in which the rate is proportional to the square of a reactant's concentration
Psychology and philosophy
*
Second-order conditioning
In classical conditioning, second-order conditioning or higher-order conditioning is a form of learning in which the first Stimulus (psychology), stimulus is classically conditioned to an unconditioned stimulus, then a second stimulus is classical ...
, a form of learning from previous learning
*
Second-order desire, the desire to have a desire for something
*
Second-order stimulus, a visual stimulus distinguished by an aspect other than luminance
Other uses
*
Second Order (religious), the cloistered nuns who are affiliated with mendicant orders of friars
{{Disambiguation