A logo (abbreviation of logotype, from Greek: λόγος logos "word" and τύπος typos "imprint") is a graphic mark, emblem, or symbol commonly used by commercial enterprises, organizations and even individuals to aid and promote instant public recognition. Logos are either purely graphic (symbols/icons) or are composed of the name of the organization (a logotype or wordmark). In the days of hot metal typesetting, a logotype was one word cast as a single piece of type, e.g. "The" in ATF Garamond (as opposed to a ligature, which is two or more letters joined, but not forming a word). By extension, the term was also used for a uniquely set and arranged typeface or colophon. At the level of mass communication and in common usage a company's logo is today often synonymous with its trademark or brand.
Numerous inventions and techniques have contributed to the contemporary logo, including cylinder seals (c.2300 BCE), coins (c.600 BCE), trans-cultural diffusion of logographic languages, coats of arms, watermarks, silver hallmarks and the development of printing technology. As the industrial revolution converted western societies from agrarian to industrial in the 18th and 19th centuries, photography and lithography contributed to the boom of an advertising industry that integrated typography and imagery together on the page. Simultaneously, typography itself was undergoing a revolution of form and expression that expanded beyond the modest, serif typefaces used in books, to bold, ornamental typefaces used on broadsheet posters. The arts were expanding in purpose—from expression and decoration of an artistic, storytelling nature, to a differentiation of brands and products that the growing middle classes were consuming. Consultancies and trades-groups in the commercial arts were growing and organizing; by 1890 the US had 700 lithographic printing firms employing more than 8,000 people. Artistic credit tended to be assigned to the lithographic company, as opposed to the individual artists who usually performed less important jobs.
Logo design is an important area of graphic design, and one of the most difficult to perfect. The logo (ideogram) is the image embodying an organization. Because logos are meant to represent companies' brands or corporate identities and foster their immediate customer recognition, it is counterproductive to frequently redesign logos. The logo design profession has substantially increased in numbers over the years since the rise of the Modernist movement in the United States in the 1950s. Three designers are widely considered the pioneers of that movement and of logo and corporate identity design: The first is Chermayeff & Geismar, which is the firm responsible for a large number of iconic logos, such as Chase Bank (1964), Mobil Oil (1965), PBS (1984), NBC (1986), National Geographic (2003) and others. Due to the simplicity and boldness of their designs, many of their earlier logos are still in use today. The firm recently designed logos for the Library of Congress and the fashion brand Armani Exchange. Another pioneer of corporate identity design is Paul Rand, who was one of the originators of the Swiss Style of graphic design. He designed many posters and corporate identities, including the famous logos for IBM, UPS, and ABC. The third pioneer of corporate identity design is Saul Bass. Bass was responsible for several recognizable logos in North America, including both the Bell Telephone logo (1969) and successor AT&T Corporation globe (1983). Other well-known designs were Continental Airlines (1968), Dixie (1969), and United Way (1972). Later, he would produce logos for a number of Japanese companies as well. Rand and Bass both died in 1996. An important development in the documentation of logo design is the study of French trademarks by historian Edith Amiot and philosopher Jean Louis Azizollah