Media relations involves working with various media for the purpose of informing the public of an organization's mission, policies and practices in a positive, consistent and credible manner. wikipedia.org

Public relations (PR) is the practice of managing the flow of information between an organization and its publics. Public relations provides an organization or individual exposure to their audiences using topics of public interest and news items that do not require direct payment. wikipedia.org

Brand is the name, term, design, symbol, or any other feature that identifies one seller's product distinct from those of other sellers

Marketing communications (MC) uses different marketing channels and tools in combination: Marketing communication channels focuses on any way a business communicates a message to its desired market, or the market in general. A marketing communication tool can be anything from: advertising, personal selling, direct marketing, sponsorship, communication, promotion and public relations. wikipedia.org

A brand is a product or service whose dimensions differentiate it in some ways from other products or services designed to satisfy the same need. A brand can take many forms, including a name, sign, symbol, color combination or slogan. wikipedia.org

Business Marketing is the practice of individuals, or organizations, including commercial businesses, governments and institutions, facilitating the sale of their products or services to other companies or organizations that in turn resell them, use them as components in products or services... wikipedia.org