ISO 10075-1:2017 defines terms in the field of mental workload, covering mental stress and mental strain, and short- and long-term, positive and negative consequences of mental strain. It also specifies the relations between these concepts involved. In this document, mental workload is regarded as an umbrella or generic term, referring to all the concepts and constructs mentioned in the document and does not have a specified or standardized meaning of its own within the document. This is consistent with the use of the term in ergonomics and its applications, where it can refer to mental stress, mental strain and their effects, i.e. both to the causes and the effects. In this document, the term mental workload will thus not be treated as a technical term but only as a reference to the domain of mental workload. NOTE Annex A gives additional explanations of terms and concepts. ISO 10075-1:2017 applies to the design of working conditions with respect to mental workload and is intended to promote a common usage of terminology between experts and practitioners in the field of ergonomics as well as in general. ISO 10075-1:2017 does not address methods of measurement and principles of task design, which are dealt with in ISO 10075-2 and ISO 10075-3.