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ENT File - What is an .ent file and how do I open it?
Learn about .ENT files and view a list of programs that open them.
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Overview
What is an ENT file? An ENT file is a plain text file that contains external entity definitions used in markup languages , such as .XML and .SGML . These entities serve as placeholders or references for content, such as special characters, text snippets, or symbols, that may appear multiple times in a document. ENT files are commonly used alongside a Document Type Definition ( .DTD ) file, which specifies the structure and rules for the markup.
More Information XML and SGML documents reference ENT files to reuse standard entity definitions without repeating them in every file. For example, an ENT file might define commonly used characters, file paths, or shared components in a documentation system. By storing this data externally, ENT files help make markup documents cleaner and easier to maintain. Developers, technical writers, and content managers who work with structured documents are the primary users of ENT files. These users often rely on ENT files to manage large sets of content efficiently and consistently.
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.ENT File Extension
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What is an ENT file?
An ENT file is a plain text file that contains external entity definitions used in markup languages , such as .XML and .SGML . These entities serve as placeholders or references for content, such as special characters, text snippets, or symbols, that may appear multiple times in a document. ENT files are commonly used alongside a Document Type Definition ( .DTD ) file, which specifies the structure and rules for the markup.
More Information
XML and SGML documents reference ENT files to reuse standard entity definitions without repeating them in every file. For example, an ENT file might define commonly used characters, file paths, or shared components in a documentation system. By storing this data externally, ENT files help make markup documents cleaner and easier to maintain.
Developers, technical writers, and content managers who work with structured documents are the primary users of ENT files. These users often rely on ENT files to manage large sets of content efficiently and consistently.
How to open an ENT file
You can open ENT files with various software that processes XML or SGML documents, such as publishing systems, document validation tools, or certain programming libraries. For example, SyncRO Soft oXygen XML Editor and Adobe FrameMaker support ENT files.
Since ENT files contain plain text, you can also open them with a plain text or XML editor, such as Microsoft Notepad and Apple TextEdit .
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Programs that open or reference ENT files
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Windows
SyncRO Soft oXygen XML Editor
Free Trial
Adobe FrameMaker
Free Trial
Microsoft Notepad
Included with OS
Any text editor
Mac
SyncRO Soft oXygen XML Editor
Free Trial
Apple TextEdit
Included with OS
Any text editor
Linux
SyncRO Soft oXygen XML Editor
Free Trial
gedit
Free
Any text editor
Category: Developer Files
Updated: August 1, 2025