What term describes a function used in an application for calculations or data manipulation?

The term that describes a function used in an application for calculations or data manipulation is "functional." In software development and design, functional requirements refer to the specific behaviors or functions of a system, detailing what the system should do, including calculations, data manipulation, and interactions with users or other systems. These requirements are essential for defining the capabilities of an application, guiding developers in creating features that fulfill user needs.

The other terms relate to different aspects of software engineering. Performance refers to the efficiency and speed of the application, which affects how well functional features operate but is not itself a function. Non-functional refers to attributes like reliability, usability, and scalability, which describe how the system performs under various conditions but do not directly involve the calculations or manipulations themselves. Traceability relates to the ability to link requirements throughout the development process, ensuring that the resulting system meets initial specifications, but it does not describe the functions themselves. Thus, functional is the appropriate term for describing the core functionalities involved in calculations or data manipulation.