page_title: Repository
page_description: Definition of an Repository
page_keywords: containers, concepts, explanation, image, repository, container

# Repository

## Introduction

A repository is a set of images either on your local Docker server, or
shared, by pushing it to a [*Registry*](/terms/registry/#registry-def)
server.

Images can be associated with a repository (or multiple) by giving them
an image name using one of three different commands:

1. At build time (e.g., `sudo docker build -t IMAGENAME`),
2. When committing a container (e.g.,
   `sudo docker commit CONTAINERID IMAGENAME`) or
3. When tagging an image id with an image name (e.g.,
   `sudo docker tag IMAGEID IMAGENAME`).

A Fully Qualified Image Name (FQIN) can be made up of 3 parts:

`[registry_hostname[:port]/][user_name/](repository_name:version_tag)`

`username` and `registry_hostname` default to an empty string. When
`registry_hostname` is an empty string, then `docker push` will push to
`index.docker.io:80`.

If you create a new repository which you want to share, you will need to
set at least the `user_name`, as the `default` blank `user_name` prefix is
reserved for official Docker images.

For more information see [*Working with
Repositories*](/userguide/dockerrepos/#working-with-the-repository)