<desc> (description) contains a brief description of the object documented by its parent element, typically a documentation element or an entity. [22.4.1 Description of Components]
When used in a specification element such as elementSpec, TEI convention requires that this be expressed as a finite clause, begining with an active verb.
Example
<desc>contains a brief description of the purpose and intended use of a documentation element, or a brief characterisation of a parent entity </desc>