Human Factors (or Human Factors Engineering)

The term Human factors refers to technical systems and equipment so designed that they can be used safely and efficiently by humans.
Reference: CCPS(1989) Guidelines for Technical Management of Chemical Process Safety
Refers to the study of human abilities and characteristics as they affect the design and smooth operation of equipment, systems, and jobs. The field concerns itself with considerations of the strengths and weaknesses of human physical and mental abilities and how these affect the systems design. In general, human factors engineering examines a particular activity in terms of its component tasks and then considers each task in terms of: physical demands, skill demands, mental workload, and other such factors, along with their interactions with aspects of the work environment (e.g., adequate lighting, limited noise, or other distractions), device design, and team dynamics.
Reference: S2S (safety to safety website: Patient Safety Network, PSNet)