An association or file association describes installed software associated with a particular file extension or file format. For example, a file with a .TXT extension is associated with Notepad or WordPad in the Microsoft Windows operating system by default. When opening a file (double-clicking the file), the default associated program opens the file. If no program is associated with the file, you’re asked to choose what program should be used.
Operating system terms
Related information
- How to associate a file with a program in Windows.
- Our file extensions overview provides further information about file associations and extensions.
- All questions relating to computer files and file extensions.