This can mean one of several things. An enclosure can be something that encloses such as a wall or a fence. In this context, it can also refer to a box or similar packaging. An enclosure may also refer to the space within the wall or fence. For example, a piece of land that is surrounded by a fence is an enclosure.

In computer language, an enclosure refers to an attachment, as in an email attachment, for example. There is also another kind of enclosure called the RSS enclosure. This is a way of attaching multimedia content to RSS feeds by providing the URL of a file associated with an entry, such as an MP3 file to a music recommendation or a photo to a diary entry. Unlike e-mail attachments, enclosures are merely hyperlinks to files. The actual data are not embedded into the feed.