Lettermark is a font based logo design used by some businesses with rather lengthy names. The initials of the business name is usually abrreviated and used as logo. For example NASA, IBM.
Similar to letter mark, word mark is also a font based logo design. If the name of the business is short, catchy and unique the same is used as the organization's design.
Example: Google, Coca cola.
Sometimes a picture or a graphic mark is used as the logo of a business. The image used should be easily remembered and immediately associated with the organization. Well established companies with strong brand image use this logo design. Sometimes, instead of an easily recognizable picture, an abstract or geometric form is used to represent the business. It called an abstract logo.
Example: Twitter, Pepsi
An illustrated character is used in this logo design to represent the business. Funny and colorful cartoons are often used in a mascot design to easily connect to children and adult customers.
Example: KFC, Pillsbury
This type of logo is a combination of letter mark or wordmark with the pictorial mark, abstract mark or a mascot representation. Since these logos are a combination of both text and image it is easy for the customer to associate the business name and mark.
Examples: Lacoste, Burger King
An emblem logo consists of text inside a symbol mainly used to represent government agencies, educational institutions, and automobile industry.
Emblem logo gives a traditional and classy appearance.
Examples: Harley Davidson, Harward University