Logotype, trademark, symbols, pictograms
A logotype (from the Greek λογότυπο), commonly known as a logo, is the graphic element, symbol, and icon of a trademark or brand, which is set in a special typeface or arranged in a particular way. The shapes, colors, fonts and images usually different from others in a similar market.
A logo is an iconic symbol designed to represent a company, product or service. It also depicts an organization's personality. The uniqueness of a logotype is of utmost importance to avoid confusion in the marketplace among clients, suppliers, users, affiliates, and the general public. To the extent that a logotype achieves this objective, it may function as a trademark, and may be used to uniquely identify businesses, organizations, events, products or services.
Source - Wikipedia.org