something that you must have or do because it is necessary or because a rule, law, or situation says so
A passport is a basic requirement for international travel.
Good eyesight is a requirement for becoming a pilot.
✦ early 15th century, from the verb “require” + “-ment”, modeled on French "réquerrement"
a clear, detailed statement of what a system, product, or project must be able to do or have
The client emailed a list of software requirements to the development team.
Before construction begins, the engineer reviews safety requirements.
✦ Sense evolved in the mid-20th century with the rise of systems engineering and software development, extending the general idea of a need to formal project specifications.
