The UK television show Dragon's Den calls the entrepreneurs who present business ideas “pitchers.”
A pitcher is an entrepreneur who makes a formal business pitch to the dragons. The pitch usually explains the product or service, the amount of money requested, the percentage of the company offered and the business's financial performance. The dragons then ask questions before deciding whether to make an offer.
The word is drawn from the language of business presentations, where an entrepreneur “pitches” an idea to potential investors. It is not a special legal status and does not necessarily mean that the entrepreneur has secured funding. A pitcher can leave with an offer, reject an offer or receive no deal.
“Founder” is also a legitimate business term, but it is broader: a founder creates or helps create a company whether or not that person appears on television. In Dragon's Den terminology, “pitcher” specifically describes the participant presenting an opportunity in the den.