A repository provides a storage mechanism for digital products. May refer to [version-control] like [git] or [svn]. An application specific tag should be used with this tag in order to identify the specific repository management interface that is being used unless the question is general in nature. See also: [repository-pattern]

A repository is a place to store digital products along with the necessary software to manage the storage and access and update the products stored there.

The Repositories Support Project in the United Kingdom provided a What is a repository? page that describes a repository as:

A digital repository is a mechanism for managing and storing digital content. Repositories can be subject or institutional in their focus. Putting content into an institutional repository enables staff and institutions to manage and preserve it, and therefore derive maximum value from it.

The article goes on to say:

Digital repositories may include a wide range of content for a variety of purposes and users. What goes into a repository is currently less an issue of technological or software ability, and more a policy decision made by each institution or administrator.

See also from Microsoft MSDN The Repository Pattern.