Marketing in common parlance is roughly equivalent to "selling". However Marketing as an academic discipline involves vocational training many other areas of business, such as advertising, public relations, product design, pricing, distribution, sales force management, and so on.
The Marketing Concept
In academia the term "Marketing" is often synonymous with the "Marketing Concept", which is a general business philosophy. Marketing scholars hold that the historical development of business "orientations" started with the "Production Orientation", which can be briefly described as "make (i.e. manufacture) as much as you can, and someone will buy it." This was replaced by the "Selling Concept" which can be summarised as "People won't buy things by themselves, you have to get out there and sell it to them." Implicit in both these orientations is that businesses decide what to produce, and how much to produce is determined by production capacity or sales-force performance, respectively. The "Marketing Concept" replaces these ideas with something along the lines of "First, find out what people actually want, and then organise ourselves to deliver it." It can be paraphrased simply as "The Customer is King." Note that in the Marketing Concept it is consumers who drive what and how much is to be produced.
The Four Ps
Marketing is sometimes defined as all those business activities that pertain to the "Four Ps": Product, Place, Price and Promotion. (By "Place" we mean all those things that are involved in shifting the product from the producer to the consumer.)
Products and Services
The term "product" in marketing has a somewhat fuzzy interpretation. It is generally acknowledged that most branded products involve some sort of service components (a warranty, for example) that is bought in addition to the purely physical product itself. Similarly, even services involve some tangible elements, for example a haircut often involves a cup of tea or coffee. Hence, we speak of the "product --- service continuum", and often when we say "product" it is understood to include everything from bags of sugar to professional services.
Branding and Differentiation
Although not implicit in any definition of marketing that has gained common acceptance, a core part of marketing in practice involves making the product "unique" in some sense. This is known as product differentiation, and can be thought of also as branding. Whatever the definition of branding, it is always more than the simple attachment of a brand name to a product. And a "Brand" is always more than the brand name.