User Interface Design is the intentional composition of elements on a device in which a user interacts with. Maximization of usability (the measurement of ease and learnability of an interface) and user experience (the user’s response to their interaction with the interface) are the two of the main considerations when designing for UI. These ideas are significant, because machines are, in most respects, made by people, for people.
For the first time we had a shared definition of our interfaces that we could use to coordinate its evolution. This not only encouraged consistency and increased efficiency, but also created a shared vocabulary between designers and developers, so that the label for a colour or type-style could be understood across design-specs and code.