A logo is an icon, symbol, or graphic element used to signal a trademark or brand. A logo is a graphic mark or emblem 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 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.

The current era of logo design began in the 1870s with the first abstract logo, the Bass red triangle. Today there are many corporations, products, brands, services, agencies and other entities using an ideogram (sign, icon) or an emblem (symbol) or a combination of sign and emblem as a logo. As a result, only a few of the thousands of ideograms people see are recognized without a name. An effective logo may consist of both an ideogram and the company name (logotype) to emphasize the name over the graphic, and employ a unique design via the use of letters, colors, and additional graphic elements.
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.
Color is considered important to brand recognition, but it should not be an integral component to the logo design, which could conflict with its functionality. Some colors are formed/associated with certain emotions that the designer wants to convey. In the United States red, white, and blue are often used in logos for companies that want to project patriotic feelings. Green is often associated with the health and hygiene sector, and light blue or silver is often used to reflect diet foods. For other brands, more subdued tones and lower saturation can communicate reliability, quality, relaxation, or other traits.
Designing a good logo is not a simple task and requires a lot of involvement from the marketing team and the design agency (if outsourced). It requires clear idea about the concept and values of the brand as well as understanding of the consumer or target group as marketers call. Broad step in logo design process would be formulating concept, doing initial sketch or sketches, finalizing the logo concept, deciding the theme colors and format.

An icon is a graphic device that represents some object or action, the graphic device being ascribed. A symbol has only the meanings ascribed to itself, representing only a concept and not recognizable as a particular object.