What is a system?
System gathers and makes sense of statistical information about how things in the world relate to one another, and then organizes those relationships into a system.
Simply put, a “system” is a collection of elements that interrelate with one another to form a unified whole based on a set of rules. (The term "system" comes from the Latin word systēma, meaning "whole concept made of several parts or members.”) Most of the systems that impact us — our bodies, the climate, the economy, our cities — are “complex,” meaning that the activity of the system cannot be measured as just the sum of the elements; they need to be measured and considered as a whole.
System is designed to support systems thinking. “Systems thinking” is a holistic approach to analysis. It focuses on the way a system's individual parts interrelate, how systems change over time, and how they work within even larger systems.