http://docs.oasis-open.org/odata/odata/v4.0/os/part2-url-conventions/odata-v4.0-os-part2-url-conventions.html#_Toc372793861
specifies that: "The $select system query option allows clients to requests a limited set of properties for each entity or complex type."

Since, in the absence of a $select, we allow the service to choose a default set of properties to return, $select can be used not only to restrict but also to expand the set of properties to be selected.

Some readers have been concerned that "limited" corresponds to the default set, as opposed to the available properties.