What is a logo? Well, this might seem a redundant question. "I create logo designs on a daily basis, you might say... I know what a logo is!" But even so, sometimes it seems hard to put it in words and give a compelling definition. We can define a logo as being a distinctive symbol, unique, with character, that belongs and visually defines a company, object, person or service. But then, we have all those other words as mark, trademark, signature, identity, brand... What should we do with those and where do they fit, as sometimes those words are used to describe a logo?
The mark is a symbol that is easy to recognize and indicates the fact that a company or person owns or produces certain goods or services.
A trademark on the other hand could be a symbol or a name that is legally registered and stands as proof to the fact that a product is made by a certain company or person.
A signature is a unique mark or a combination of graphic elements that visually define a product, company or person. A graphic style guide that is applied to all communication or marketing materials could be called a signature.
A wordmark is composed of the company name in custom designed or specially modified font and it is used as the company logo. The main disadvantage of the wordmark is that it might look generic and it is not be as easy to recognize.
The symbol is actually the icon part of the logo and may be used without the wordmark in some cases to identify a company. Think for example of the Apple's apple or Nike's swoosh. "A picture is worth a thousand words" might the main advantage for a symbol only logo, but in the same time, if the symbol is separated from the text part of the logo and the mark does not have equity it may be difficult to recognize.
In some cases, when the company name is too long, a monogram which is a design of one or few letters (usually initials) is used to identify a company or service. A monogram has higher visual impact and it is easier to recognize than a long wordmark, but it needs repeated viewing and audience contact to get a higher mnemonic value.
A company's visual identity includes the logo design, but goes further and comprises the fonts used, specific set of colors and imagery that graphically define a company, service or person. The identity is not a brand. "The logo is not a brand, unless it's on a cow" states a famous saying. When you design a logo you cannot make a brand. With designing a logo and a visual identity system a designer lays the foundation of a company's message, but the brand is built by the company's audience, as the brand is the perception that the target audience has about a certain company.