<graphics> A small picture intended to represent something (a file, directory, or action) in a graphical user interface. When an icon is clicked on, some action is performed such as opening a directory or aborting a file transfer.
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 Dynamically Linked Library (DLL) files.
The term originates from Alan Kay's theory for designing interfaces which was primarily based on the work of Jerome Bruner. Bruner's second developmental stage, iconic, uses a system of representation that depends on visual or other sensory organization and upon the use of summarising images.
[What MS tool can create .ico files?]