We often use words when communicating, but there are also other ways to communicate. Let’s briefly talk about icons, indexes, and symbols.
An icon represents the real life item that it is supposed to stand for.
For example, the following would be considered an icon for a camera:
An index is closely related to another object, often in a causal relationship.
The below cloud can be used to represent rain when shown on a weather forecast.
A symbol has an arbitrary relationship with the object or concept that it represents.
The below symbol is called a “hamburger menu icon” in webdesign; however, it’s considered a “symbol” in a linguistics sense. The below symbol is just three lines and represents an action to open a menu.