According to ISO standards, user experience is defined as “a person's perceptions and responses that result from the use or anticipated use of a product, system or service.”1
However, I will twist this basically correct definition a little. I would describe user experience as the feelings that the user gets when using a product. Using feelings as a comparison model allows us to understand that the user experience can be anything from hate to love. From anger to happiness. From indifference to passion. From expectance to nostalgia. From pride to humiliation. And so forth.