UX Depicts User Experience were UI Depicts User Interface.Both names conspicuously they are same ,but they are different know why:
UX design deals with the overall experience associated with the use of a product or service.UI design deals with the specific user interface(s) of a product or service. The UI can be a component of UX, but many user experiences don't have UIs. The design of a UI will be heavily informed by the UX design. The UX design will be less informed by the UI.
For example : User Experience:
You See an iPhone and you feel awesome ..This is positive User experience
You Seen an Bad weird phone .This is negative User experience ..
user experience design (none specific to field) - concept of designing user experience, which in turn includes visual design and interaction design plus the limitations of the field in which such design work is happening
For example : User interface:
user interface (some what specific to field) - concept of designing an interface through which user can interact with the product, gui in soft/web app or an steering wheel in a car
user interface development (none specific to field) - is a process of converting user interface design concept into functioning interface that creates physical connection between individual and product.