UI, where I stands for "interface" just like in HCI, used to mean all those things.
But in the industry the focus turned to aesthetics, so a new term was invented to differentiate between focusing on the entire interface ("experience") vs just the look.
Just like "design" encompasses all of it, but we add qualifiers to ensure it's not misunderstood for "pretty".
But in the industry the focus turned to aesthetics, so a new term was invented to differentiate between focusing on the entire interface ("experience") vs just the look.
Just like "design" encompasses all of it, but we add qualifiers to ensure it's not misunderstood for "pretty".