The icon is the simplest since it is a pattern that physically resembles what it `stands for' and are directly related to what they display.
Example of icons:
1. Statue of Liberty
The Statue of Liberty is a direct visual reference to the state of New York.
Also, many people associate it with the United States and freedom. It has many different meanings and is truly an icon.
2.The picture of a smoking cigarette with a diagonal bar
across the picture is an icon that directly represents
`Smoking? Don't do it'.
Symbols
Are often abstract and have to be learned by the viewer seeing what the symbol represents a few times.
The symbol consists in a natural or conventional or logical rule, norm, or habit, a habit that lacks (or has shed) dependence on the symbolic sign's having a resemblance or real connection to the denoted object. Thus, a symbol denotes by virtue of its interpretant. Its sign-action (semeiosis) is ruled by a habit, a more or less systematic set of associations that ensures its interpretation. For Peirce, every symbol is a general, and that which we call an actual individual symbol (e.g., on the page) is called by Peirce a replica or instance of the symbol. Symbols, like all other legisigns (also called "types"), need actual, individual replicas for expression. Theproposition is an example of a symbol which is irrespective of language and of any form of expression and does not prescribe qualities of its replicas.
source:wikipedia
eg:
A word that is symbolic (rather than indexical like "this" or iconic like "whoosh!") is an example of a symbol that prescribes qualities (especially looks or sound) of its replicas.
IMPORTANT CLAIM:
No living nonhuman animals are able to use word-like symbols.
[There are some assertions that a few individual animals use a small (< 50 item) inventory of symbol-like units using hand signs or small physical tokens.]
If this claim is true, it implies
Nonword Symbols.
The most common use of the term symbol is for signs that are not words:
So, nonword symbols are much like words but often lack a phonetic form.
source:http://www.cs.indiana.edu/~port/teach/103/sign.symbol.short.html
Index
Most road signs are index because they directly illustrate what you should or should not do/watch out for.
e.g
1.wet floor sign
The wet floor sign points directly at the meaning through the image of a person slipping.
2.Big house
The big house shows the meaning of the wealth..
source:gubuk-reok.blogspot.com
