What does a 'container' refer to in container terminology?

In container terminology, a 'container' specifically refers to a runtime instance of an image. This means that when an image, which is a packaged application including everything it needs to run, is instantiated, it creates a container. The container encapsulates the application and its environment, ensuring that it runs consistently across different computing environments.

This definition is crucial because it emphasizes the dynamic nature of containers. They are not just static images; they are live, executable units of software that contain the application as well as all its dependencies, configurations, and runtime instructions. This concept allows for great flexibility and scalability in application deployment.

Other concepts related to container technology, such as storage and delivery systems for images, collections of images, or variable metadata, play important roles in the overall container ecosystem but do not define what a container is. These terms refer to different aspects of image management or packaging rather than describing the active running environment that a container represents.