functional requirement; capability requirement
Technical term in systems engineering and software development, specifying what a system or component must do.
In this project, we first need to clearly define the functional requirements.
It is important to understand the difference between functional and non-functional requirements.
非機能要件 refers to non-functional requirements (performance, security, etc.), while 機能要件 specifies what the system should do.
Compound of 機能 (function) and 要件 (requirement). A modern technical term likely calqued from English 'functional requirement'.