Requirement

A requirement is a necessary circumstance or condition for something.

It can be used in many different areas. A job offer may require a vehicle of its own and higher studies, thus excluding applicants who do not meet these conditions. In order to be able to vote in a certain country, a number of requirements must be met, such as being of legal age and having the nationality in that country. Likewise, a nightclub can establish as entry requirements such as being of age and going well dressed.

System engineering uses the term requirement in an analogous sense as a necessary condition for the content, form or functionality of a product or service.

wiki