техническое задание(A functional specification (also, functional spec, specs, functional specifications document (FSD), functional requirements specification) in systems engineering and software development is a document that specifies the functions that a system or component must perform (often part of a requirements specification) (ISO/IEC/IEEE 24765-2010). The documentation typically describes what is needed by the system user as well as requested properties of inputs and outputs (e.g. of the software system). A functional specification is the more technical response to a matching requirements document, e.g. the Product Requirement Document "PRD". WK Alexander Demidov)
функциональная спецификация(A document that describes a solution, product feature set, or other final project deliverable in explicit detail. It includes the conceptual, logical and physical designs)
функциональные требования(функциональная спецификация; отдельный документ или часть технического задания, где описывается, что должна делать система. Разрабатывается на ранних стадиях проектирования ssn)
