Philately is the study of revenue or postage stamps. This includes the design, production and uses of stamps after they are issued by postal authorities. Although many equate it with stamp collecting, it is a distinct activity. For instance, philatelists will study extremely rare stamps without expecting to own copies of them, whether because of cost, or because the sole survivors are in museums. Conversely, a stamp collector may choose to acquire and arrange the little pictures without being much troubled about their origin or usage. In practice, a basic knowledge of philately will save the collector from spending a great deal of money on a stamp that is really almost worthless.
From Wikipedia
