ECS

For a beginners introduction to ECS and how Cities: Skylines 2 uses ECS, please check out "Guide - ECS" that goes into more depth.

• Entity
• Component
• System
• Query
• World
• Phase
• Archetype

Basic architecture:

One Entity, Has one or more Components.

Systems run independently and are part of the Game Loop. Systems usually Query for Components, then act based on the data they retrieve, possibly mutates data inside the Components too.