A logo is a graphic mark, emblem, or symbol used to aid and promote public recognition. It may be of an abstract or figurative design or include the text of the name it represents as in a logotype or wordmark.
Symbol
A symbol is a mark, sign, or word that indicates, signifies, or is understood as representing an idea, object, or relationship. Symbols allow people to go beyond what is known or seen by creating linkages between otherwise very different concepts and experiences. All communication and data processing is achieved through the use of symbols.