Talking about icon, I think that it is important to know firstly its defintion in information & communication technology. Secondly, it is also necessary to know its former usage. As we know, icon is not a new term created by information & communication technology. Thus, it helps us to understand its application in the web well.

Definition (computer science)

Icon suggests similarity to material in next node (term in the information & communication technology by White). Here, based on Peirce's system, Mr. White, professor of Ball State University gives such definition. In ICT, as I explained before, signs are the common language which make the communication possible btw humans & computer.

Icon, a category of sign, is an image created from its nature, its resemblance. However, in Mr. White's paper, "Peirce's language", he says, according to Peirce's terms, not all images are truly icons. Therefore, the icon of a single link does not necessarily require the link be presented by an image to be iconic. In this case, both a picture of a cat & a single link stating, "cats eat mice" are funtioning iconically as links.

Former usage

• religious painting: portrait of Christ
• photography, advertisement, cinema, fashion ...

As we said previously, an icon is just like an image or more simply a picture. Thus from its ancien & common meaning, the first usage of icon was back to VIe century. In this period, icon was a type of wooden painting developped in Byzance for religious practices. This is called iconography. As iconography is different from our subject and I will not develop this point further. Here, I mention it just for its usage purpose. (iconography: the way that a particular people, religious or political group etc represent ideas in pictures or images).

Then, icon always devoted to religious practices during several centuries. And only recently, its usage extends to many fields: photography, advertisement, cinema, mode and now IT etc.

Application in computer sciences

In a computer's graphical user interface (GUI), an icon is an image that represents an application, a capability, or some other concept or specific entity with meaning for the user. An Icon is usually selectable but can also be a nonselectable image such as a company's logo.

Talking about the usage of icon in computer science, icon is firstly used massively in a computer's graphical user interface. Here, icon is presented by an image which represents an application, a capability, etc. For instance, the image of E with a circle going across it, this icon represents an application which we programed in advance so as to prevent the long process to start up the internet explorer's function. Another example, the image of a printer shows us a capability which we click on it, we can go to the printing function.

Attention: some company's logo can function as link. EX.: some web sites propose you to link by clicking on the logo of the company.

On a Web page, an icon is often a graphical image that represents the topic or information category of another Web page. Frequently, the icon is a hypertext link to that page. Typically, icons are gathered in one or two places on a page, either as separate graphic files or as a single image map.

On the Yahoo! news website you find a list of topics. You can click on either of them. It directs you to the concerned webpage. Also, you can find the same topics with headlines below.