Icon

In computing, an icon is a small picture intended to represent something (a file, directory, or action) within a graphical user interface. When an icon is clicked on or tapped, some type of action is performed, such as launching software, opening a directory, or aborting a file transfer.

History
The term originates from Alan Kay's theory for designing interfaces which was primarily based on the work of. Bruner's second developmental stage, iconic, uses a system of representation that depends on visual or other sensory organization and upon the use of summarizing images.

Usage
Icons are usually stored as bitmap images. Microsoft Windows uses a special bitmap format with file name extension ".ico" as well as embedding icons in executable (".exe") and (DLL) files. In classic Mac OS, icons were stored in the resource forks of files. As of macOS 11 "Big Sur", icons are stored in PNG format.