ISO/IEC 11581 defines graphical symbols for use on a screen, which users can manipulate and interact with. They are part of a graphical interface that can facilitate the user's ability to learn, understand and remember functional elements of the system, and aid in the manipulation of these elements. Their purpose is to facilitate interaction between computer-based applications (software products) and users.
ISO/IEC 11581-5:2004 describes user interaction with and appearance of tool icons on the screen. These tool icons are a subset of the interactive icons that modify graphical or text elements of an application by association with real-life tool objects. These icons represent tool functions such as drawing, painting or modifying graphical elements. ISO/IEC 11581-5:2004 contains requirements and recommendations for 21 commonly used tool icons. It also specifies the relationship between tool and pointer icons.