noun
functional requirement; capability requirement
Technical term in systems engineering and software development, specifying what a system or component must do.
このプロジェクトでは、まず機能要件を明確に定義する必要がある。
In this project, we first need to clearly define the functional requirements.
機能要件と非機能要件の違いを理解することが重要です。
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'.