noun
document type definition; DTD
Technical computing term for the formal definition of a document structure in markup languages such as XML or SGML.
XML文書の妥当性は文書型定義に従って検証される。
The validity of an XML document is verified according to the document type definition.
Compound of 文書 (document), 型 (type), and 定義 (definition), likely a calque from English 'document type definition'.