the activity, set of institutions, and process for creating, communicating, delivering, and exchanging offerings that have values for customers, clients, partners, and society at large.
American Marketing Association
the science and art of exploring, creating, and delivering value to satisfy the needs of a target market at a profit.
Dr Philip Kotler, What is Marketing?
the art and science of finding prospects – people who are actively interested in what you have to offer.
Josh Kaufman, Personal MBA, Chapter 2: Marketing