We are all very familiar with objects that symbolize something. Perhaps you're familiar with the lit up light bulb to symbolize a great idea that someone's had. And everybody knows the symbols we use in Mathematics on an everyday basis: + (add), - (subtract), x (multiply), / (divide), = (equals), < (less than), and > (greater than). Then there's the percent sign (%) that means a part of one hundred, the dollar sign ($) which stands for money, the (&) sign which means "and", and the number sign (#). The # sign can also stand for the number of pounds that something weighs.
The American bald eagle is used as the symbol of the United States because an eagle is strong, it soars between heaven and earth, and it isn't afraid of anything. The American flag itself is made up of colors that symbolize three things: red (courage and valor), white (purity and innocence), and blue (vigilance, perseverance, and justice). An olive branch has been used for centuries as a symbol of peace.
Chemistry is full of symbols. Just take a look at the Periodic Table of the Elements and you can see one or two letters that each represent a natural element. One such example is the letter "O," representing the element oxygen.
The Chinese have symbols for everything. Two well-recognized ones are "yin" and "yang," which mean "dark" and "light." The two placed together make up a complete circle and represent balance and completeness. The one is not without the other.
These are just a few of the symbols I know of.