[EN ISO 26800:2011, 2.2]:scientific discipline concerned with the understanding of interactions among human and other elements of a system, and the profession that applies theory, principles, data and methods to design in order to optimize human well-being and overall system performance.Note 1 to entry: This definition is consistent with that given by the International Ergonomics Association[EPA, Terms & Acronyms Glossary]:the study of people adjusting to their work environment; the science of adapting working conditions to the worker.