Glossary
New to systems science? These are the foundational concepts — the shared language for analyzing any complex system.
The Basics
System An organized set of interacting components forming a coherent whole, with identifiable boundaries separating it from its environment.
Boundary The demarcation separating a system from its environment, including the interfaces where exchanges occur. Controls what flows in and out.
Environment Everything outside the system boundary — the sources providing inputs, the sinks receiving outputs, and the channels through which flows occur. The Parts
Component A distinct part within a system that performs specific functions and interacts with other components through defined interfaces.
Subsystem A component inside a system that is itself a system — with its own boundaries, components, and behaviors. Systems nest within systems.
Interface A connection point where a system meets its environment or where components connect to each other. Where exchanges happen. The Dynamics
Flow The movement of matter, energy, or messages between components or across boundaries. The substance transfers that keep systems functioning.
State The configuration of a system at a specific moment — the values of its variables and relationships between components right now.
Feedback Loop A circular process where a system's output returns to influence its input. Can amplify (positive) or stabilize (negative) system behavior.
Adaptation How a system modifies itself in response to changes — adjusting structure or behavior to maintain functionality or improve fitness. The Patterns
Structure The arrangement and relationships between components — how the system is organized. Structure enables and constrains what the system can do.
Function What a system or component does — its role, purpose, or activity. Different structures can perform the same function.
Emergence When complex patterns or behaviors arise from simpler component interactions — properties the whole has that the parts don't have alone.