# Terminology

* ***Images*** - The blueprints of our application which form the basis of containers. In the demo above, we used the `docker pull` command to download the **ubuntu** image.
* ***Containers*** - Created from Docker images and run the actual application. We create a container using `docker run` which we did using the ubuntu image that we downloaded. A list of running containers can be seen using the `docker ps` command.
* ***Docker Daemon*** - The background service running on the host that manages building, running and distributing Docker containers. The daemon is the process that runs in the operating system which clients talk to.
* ***Docker Client*** - The command line tool that allows the user to interact with the daemon. More generally, there can be other forms of clients too - such as [Kitematic](https://kitematic.com/) which provide a GUI to the users.
* ***Docker Hub*** - A [registry](https://hub.docker.com/explore/) of Docker images. You can think of the registry as a directory of all available Docker images. If required, one can host their own Docker registries and can use them for pulling images.