A scale or full-size model of a design or device which is not fully functional, used for teaching, demonstration, design evaluation, promotion, and other purposes.
A prototype, usually low-fidelity, such as a paper illustration, screenshot, or simple configuration of a screen with limited interaction.
Caused by the following symbol.
One of the compounds that participates in the chemical reaction that produces another compound.
That which precurses: a forerunner, predecessor, or indicator of approaching events.