Model or preliminary implementation of a piece of software suitable for the evaluation of system design, performance or production potential, or for the better understanding of the software requirements. [ ISO/IEC 15910 ]
Prototype [ ISO/IEC/IEEE 24765 ]: A preliminary type, form, or instance of a system that serves as a model for later stages or for the final, complete version of the system.
- A prototype is used to get feedback from users for improving and specifying a complex human interface, for feasibility studies, or for identifying requirements. [ ISO/IEC/IEEE 24765 ]