file association - Computer Definition
(1) The relationship of one file to another based on the data it contains.
(2) An established relationship between a file and the application used to open it. There are default file associations pre-configured in every operating system for all the common file types. However, if a file's icon or name is clicked without a default association, the OS prompts the user for the application to use. File associations can be easily changed (to learn how in Windows, see Win File association).