What is DTD? DTD, short name for Document Type Definition, is used as the file extension for Document Type Definition files. .DTD files are text files that can be opened by Notepad or any text editors. See the sample .DTD file included below.

File Extension: .DTD

MIME Type: text/plain

File Content: Document Type Definition

.DTD files are Document Type Definition files, which are used to provide element and attributes definitions for a group of XML files. Here is a sample .DTD Document Type Definition file, image.dtd:

<?xml version="1.0" encoding="UTF-8"?>
<!--
  Copyright 2000, 2010 Oracle and/or its affiliates.
  ...
-->

<!ENTITY % url "CDATA">

<!-- URI reference -->
<!ENTITY % uriReference "CDATA">

<!-- a color value having the format #rrggbb -->
<!ENTITY % color				"CDATA">

<!-- determine the mask mode of the image bitmap -->
<!ENTITY % maskMode "(maskcolor|maskbitmap)">

<!ELEMENT image:entry EMPTY>
<!ATTLIST image:entry
	image:command %url; #REQUIRED
	image:bitmap-index CDATA #REQUIRED
>

<!ELEMENT image:externalentry EMPTY>
<!ATTLIST image:externalentry
	image:command %url; #REQUIRED
	xlink:href %uriReference; #REQUIRED
	xlink:type CDATA #FIXED "simple"
>

<!ELEMENT image:externalimages (image:externalentry*)>
<!ELEMENT image:images (image:entry*)>
<!ATTLIST image:images
	xlink:href %uriReference; #REQUIRED
	xlink:type CDATA #FIXED "simple"
	image:maskmode %maskMode; "maskcolor"
	image:maskcolor %color; "#000000"
	image:maskurl %url; #IMPLIED
>

<!ELEMENT image:imagescontainer (image:images*, image:externalimages?)>
<!ATTLIST image:imagescontainer
	xmlns:image CDATA #FIXED "http://openoffice.org/2001/image"
	xmlns:xlink CDATA #FIXED "http://www.w3.org/1999/xlink"
>

.DTD Document Type Definition file sample: Click sample.dtd to download.

Since .DTD files are in text format, you can use Notepad or any text editor to create or modify them. No special software is needed.