the original or model on which something is based or formed.
[O]n an individual basis our definitions and descriptions of what constitutes a “prototype” vary greatly. Prototypes have been described as hi-fidelity, lo-fidelity, functional, nonfunctional, paper, Flash®, HTML, interactive, non-interactive, click-through, garden variety walk-through, cognitive walk-through—the list just keeps going.
When I refer to a prototype, I'm referring to something that, from my book, "regardless of its fidelity, functionality, or how it’s made, a prototype is a conceptual model that captures and communicates the vision, intent, or idea of a design."
Source: "Definition of a Prototype." by Todd Zaki Warfel. Rosenfeld Media.
Also known as: Prototypes, Paper Prototyping, Rapid Prototyping