A short definition:
The process of planning and executing the conception, pricing, promotion, and distribution of ideas, products, and services to create exchanges that will satisfy the needs of individuals and organizations. Marketing a product involves such tasks as anticipating changes in demand (usually on the basis of market research), promotion of the product, ensuring that its quality, availability, and price meet the needs of the market, and providing after-sales service.
From: A Dictionary of Business and Management. Ed. Jonathan Law. Oxford University Press, 2009 - Available from Oxford Reference.