There is no specific TEI tag for the category or type of text, so different projects have found different approaches to the encoding of this information. One approach was to use a bespoke <rs> (reference string) element, with type of "textType", around the relevant word in the edition, often in the title:
Another approach is to include the category of text in a list of keywords in <msContents>/<summary>:
Perhaps the most TEI-compliant, although least specific, solution would be to include text category information in <textClass>/<keywords>:
General keywords or index terms of any other kind can be tagged (by default using <rs>, but any other semantically appropriate element may be captured for this purpose) anywhere in the document where they appear in running text: e.g. in the Greek or Latin edition, translations, commentary, or any of the descriptive fields in the header. Depending on the needs of a particular project and any internal or external taxonomies in use, such a tag might look something like:
The above examples could be indexed using project-specific code for the purpose of generating indices, a search form, or for sorting or filtering texts. If a taxonomy is also in use, the <rs> may carry ref for the purpose of normalizing to a term in this taxonomy. In the example below, normalization is to the EDR vocabulary for materials (see Rei Material GoogleDoc):
You can align your definitions by aligning to a local or to an external Controlled Vocabulary.
General keywords that do not belong in any particular part of the text or supporting data of the edition may be gathered conveniently in a <keywords> element in the header. These keywords will generally be used only for purposes of search, indexing, or compatibility within a larger collection, rather than appearing in the human-readable part of the edition.
For keywords, subject terms or descriptions that apply specifically to the categorization or definition of the text, the <msContents> and <summary> may be used to contain either a list of terms or general prose description, as in the examples below: