MIME type - technical definition

A file identification based on the MIME encoding system. The MIME type has become the de facto standard for identifying content on the Internet. For example, in order to identify the type of attachment sent in an e-mail message, its MIME type is embedded in the message header. Web servers send the MIME type to the requesting browser so that it can launch the appropriate helper application or plug-in.

The MIME "Content Type" has a type and subtype separated by a slash; for example, text/plain and image/gif. The major types are application, audio, image, text and video. Application refers to a variety of formats; for example, application/x-pdf refers to Adobe Acrobat documents, and application/octet-stream refers to an .EXE file. See MIME.