Why is there so much confusion between the terms Ergonomics, Biomechanics, Human Factors, User Interface Design, and Human-Computer Interface?
There are several problems when trying to define and describe each discipline including: (a) the disciplines overlap each other in terms of their activities, (b) the terms are used differently in Europe and the U.S., (c) people differ on their use of the terms, (d) the popular use of the terms often differ from the technical usage, and (e) the terms are used differently in the software industry and the hardware industry (particularly usage between large-scale systems like aircraft or nuclear power plants and the computer industry). Having said that, the responses below are an attempt to describe each discipline from our point of view.
