The study of how to improve the fit between the physical demands of the workplace and the employees who perform the work. That means considering the variability in human capabilities when selecting, designing, or modifying equipment, tools, work tasks, and the work environment.
Merriam-Webster Online Dictionary
ergonomics (noun plural but singular or plural in construction)1.
an applied science concerned with designing and arranging things people use so that the people and things interact most efficiently and safely - called also biotechnology human engineering human factors
2.
the design characteristics of an object resulting especially from the application of the science of ergonomics
human factors, workplace design, comfort engineering, user-centered design, occupational health