TEI stands for "Text Encoding Initiative."

The TEI, which is not affiliated with any institution, is a consortium dedicated to developing and maintaining a standard for ways in which texts are represented digitally.

It issues a set of Guidelines, which are regularly updated, that describe and define encoding methods for texts, such as which elements of a markup language should be used for the specific individual components and concepts that can appear in a text. These Guidelines have become the international standard used by many digitization projects in linguistics, the social sciences, and the humanities, including the Walt Whitman Archive.