A group of functions (capabilities, capacities, etc.). When a vendor says "the feature set for the next version of our software is frozen," it means all enhancements and new capabilities have been determined and planned for development.
The term is sometimes used in a communication session in the initial setup stage. For example, "negotiating or establishing the feature set" means determining the capabilities of the receiving device in order to set the highest speed, best compression method or other characteristics of the transmission. See
scope creep.