What does DTD refer to in regards to documents?

Answer 1

In reference to computers DTD stands for document type definition. It is defined as,

"a set of markup declarations that define a document type for SGML-family markup languages (SGML, XML, HTML). DTDs use a terse formal syntax that declares precisely which elements and references may appear where in the document of the particular type, and what the elements' contents and attributes are."

- wikipedia

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Answer 2

It depends on the type of document. In a legal document for a trust, DtD is sometimes used to refer to the date of the trust document. In computer documents, it is a document type definition. In other words, the DTD tells the computer what type of document it is reading.