A customer (also known as a client, buyer, or purchaser) is the recipient of a good, service, product, or idea, obtained from a seller, vendor, or supplier for a monetary or other valuable consideration. Customers are generally categorized into two types:

• An intermediate customer or trade customer (more informally: "the trade") who is a dealer that purchases goods for re-sale.
• An ultimate customer who does not in turn re-sell the things bought but either passes them to the consumer or actually is the consumer.

A customer may or may not also be a consumer, but the two notions are distinct, even though the terms are commonly confused. A customer purchases goods; a consumer uses them. An ultimate customer may be a consumer as well, but just as equally may have purchased items for someone else to consume. An intermediate customer is not a consumer at all. The situation is somewhat complicated in that ultimate customers of so-called industrial goods and services (who are entities such as government bodies, manufacturers, and educational and medical institutions) either themselves use up the goods and services that they buy, or incorporate them into other finished products, and so are technically consumers, too. However, they are rarely called that, but are rather called industrial customers or business-to-business customers. Similarly, customers who buy services rather than goods are rarely called consumers.

Ein Kunde ist eine Person oder eine Institution, die ein offensichtliches Interesse am Vertragsschluss zum Zwecke des Erwerbs eines Produkts oder einer Dienstleistung gegenüber einem Unternehmen oder einer Institution zeigt.

Un client, au sens économique, est l'acheteur d'un bien ou service, de façon occasionnelle ou habituelle, à un fournisseur (voir commerce).

En kund är en fysisk eller juridisk person som köper eller hyr en produkt eller en tjänst från ett företag eller en person. En presumtiv kund är en fysisk eller juridisk person som utgör potential till att bli kund, vilka tillsammans utgör en marknad.

Asiakas on henkilö, laite, ohjelmisto tai organisaatio, joka tilaa tai käyttää tuotetta tai palvelua.