interaction
UX (user experience)
The entirety of a person's experience with a product or company – before, during and after they touch the interface.
UX covers whether the product solves a real problem, whether the path to it makes sense, how the person feels at each step – including the parts that never appear on screen at all: the onboarding email, the support call, the invoice. If UI is the house’s walls and handles, UX is whether the house works for the life you live in it.
The term went mainstream through Don Norman’s “User Experience Architect” role at Apple in the early 1990s – deliberately coined to be broader than “interface” or “usability”. Norman’s own honest account: he credits the name to his group, and notes Brenda Laurel had used the exact phrase in 1986. The point of the width survives the origin story: the experience includes everything, not just the pixels.