Logos

After researching logos, I’ve found that they can take the form of either a symbol/icon, a logotype (a company’s unique typeface), or the more common combination of the two. A logo’s purpose is primarily to gain recognition from consumers, which leads to the trust of the brand it is associated with. Logos play a big role in business and advertising, and their colors, fonts and images scarcely repeat between companies in the same industry. Logos can also be used outside of the businesses world; For example the red cross logo.
(information from www.wikipedia.com)

The image at the top is of The Hershey Company’s logo; It is a combination of logotype and a symbol, as the dark brown rectangle is a representation of their product (chocolate).

Sign-a thing whose presence or occurrence indicates the probable presence, occurrence, or advent of something else.
Symbol-a material object representing something, often something immaterial
Icon-a sign or representation that stands for its object by virtue of a resemblance or analogy to it.
(definitions from www.dictionary.com)