noun
document type specification
Computing term for a formal description of a document's structure, often used in markup languages like SGML or XML.
SGMLでは文書型指定が文書の構造を定義する。
In SGML, the document type specification defines the structure of the document.
文書型定義 (DTD) is a specific type of document type specification used in XML/SGML; 文書型指定 is a broader term.
Compound of 文書 (document), 型 (type), and 指定 (specification). A technical term likely calqued from English 'document type specification'.