System (general concept)

A system is an organized set of interrelated components functioning as a whole. This article explains definitions, parts, history, common types, and practical examples across natural, engineered, and conceptual systems.

Author: Leandro Alegsa Creation date: November 13, 2022 Last updated: April 18, 2026

Overview

A system is an organized collection of parts or elements that interact according to regular relations to produce behavior not evident in its individual components. Systems can be physical (for example, a car engine), natural (for example, a star system), or abstract (such as a classification system). They may be tangible or conceptual and are defined by their components, boundaries, relationships, inputs and outputs. For a general introduction to how systems are treated across disciplines, see related resources.

Characteristics and components

Most systems share a set of common features that help describe their structure and function:

Components: discrete elements or subsystems that perform roles.
Boundaries: a conceptual or physical limit that separates the system from its environment.
Interactions: flows of energy, matter, information, or influence among components.
Feedback: processes that return part of the output to influence future behavior.
Purpose or function: the outcome or behavior the system tends to produce.

History and development

The systematic study of systems grew in the 20th century with developments in engineering, biology and social sciences. Interdisciplinary movements such as general systems theory and cybernetics emphasized relationships, feedback and hierarchical organization rather than isolated parts. Systems thinking later influenced management, ecology and computing, encouraging holistic analysis of complex problems.

Types and examples

Systems are usually classified by domain and scale. Examples include natural systems (ecosystems, weather), engineered systems (a car engine — see engine example, power grids), astronomical systems (a star system — see astronomical example), and abstract organizational systems (taxonomies, legal frameworks — see conceptual systems). Subsystems are systems contained within larger systems; in computing and networking, components such as a disk subsystem illustrate how subsystems support broader functions (technical example).

Importance and distinctions

Seeing a set of elements as a system helps explain emergent properties, where the whole behaves differently than the sum of its parts. Distinctions such as open versus closed systems (whether they exchange matter or energy with their surroundings), deterministic versus stochastic behavior, and hierarchical versus networked organization are useful when analyzing design, resilience, and change. Systems thinking encourages attention to connections, unintended consequences, and long-term behavior rather than isolated fixes.

Studying systems supports disciplines from engineering and biology to policy and management. Whether designing a machine, managing a supply chain, or understanding an ecosystem, recognizing parts, interactions and feedback leads to clearer analysis and more robust solutions.

Any system is, in general, a definable whole consisting of different parts that are somehow interconnected in an orderly fashion; specifically, there are a variety of different systems with their own characteristics

Concept of system theory

→ Main article: Systems theory

Systems theory refers to research directions of various disciplines that describe complex interrelationships by means of general theories on the functioning of systems in general. Around 1950, Ludwig von Bertalanffy (1901-1972) was the first to define systems as interaction contexts that are distinct from their environment, which in turn consists of other interaction contexts. According to basic ideas widespread in this context, systems can be understood as self-organizing functional units that produce their own continued functioning (cf. autopoiesis) and differentiate themselves from their environment in specific ways, for example by developing specific modes of differentiation. An example: Sailors put certain animals on an island in order to be able to hunt them there later. Thereby the system of animals and plants existing on the island until then gets "mixed up"; a new system develops. Sometimes endemics (= plants or animals that only occur in a certain, spatially clearly delimited environment) arise. In disciplines dealing with living organisms, systemic psychology and biology as well as sociology, living systems are distinguished from systems of a different nature.

System concept of structural linguistics

Structural linguistics (see structuralism) is based on the view that the meaning of individual linguistic elements is not determined by themselves, but by their relations to other elements - whereby their wholeness is described as a system with, among other things, this general property.

Engineering

For I&C, IEC 60050-351 defines a system as a "set of interrelated elements that are viewed as a whole in a particular context and are considered distinct from their environment."

In Functional Safety and SOTIF, a system is defined as a combination of sensor or signal input, logic (especially with microprocessor control), and actuators or signal outputs.

Questions and Answers

Q: What is a system?

A: A system is a group of related things that work together as a whole.

Q: Can systems only be man-made things?

A: No, systems can also be natural things like a star system.

Q: What are concepts made by people to organize ideas called?

A: They are called systems.

Q: What is a subsystem?

A: A subsystem is a system that is part of some larger system.

Q: Can subsystems only be man-made things?

A: No, subsystems can also be natural things like a disk subsystem in computer networking.

Q: Can an imaginary group of related things be called a system?

A: Yes, imaginary groups of related things can also be called systems.

Q: Can a car engine be considered a system?

A: Yes, a car engine can be considered a man-made system.

Author

Creation date: November 13, 2022

Last updated: April 18, 2026