A prototype is an early, trial version of a product/service made to test and improve ideas before the final version is created. Prototype is a preliminary, often incomplete, version of a product, ...

Opinions expressed by Entrepreneur contributors are their own. Amazon Fire Phone, Google Glass, New Coke and Nintendo’s Virtual Boy: What do all these products have in common? They didn’t sell.

Start-up Archer Aviation has finished assembling a prototype of its in-development electric air taxi Midnight and aims to begin flight testing the aircraft this summer. The prototype is not, however, ...