User: Human using an Interface. Also known as “person”, "client", "customer" or "client of client", "customer of customer”, “reader”, “shopper” or whatever you may call the person that uses your product. The word itself has a bad rep because of drug addicts. Some claim that human, person, "I", "you" or "they" would be a more appropriate word. Others say "user" is an abstract, technical term, very well understood and without magical impact on the design of a product. The discussion on how to call the user something other than user is a classic case of Everybody is always somewhat right.